The present invention provides a novel arginine mimic, (2S)-2-amino-4-(2-amino-(3,4,5,6-tetrahydropyrimidin-4-yl))butanoyl, methods of using the same, peptides that bind to biological receptors containing the same, and pharmaceuticals comprising the same.
The pharmaceuticals are comprised of a targeting moiety that binds to a biological receptor, an optional linking group, and a therapeutically effective radioisotope or diagnostically effective imageable moiety. The therapeutically effective radioisotope emits a particle or electron sufficient to be cytotoxic. The imageable moiety is a gamma ray or positron emitting radioisotope, a magnetic resonance imaging contrast agent, an X-ray contrast agent, or an ultrasound contrast agent.
JP 07/030037 describes antithrombotics of the following formula. 
Compounds of this sort are not considered to be part of the present invention.
U.S. Pat. No. 5,332,745 illustrates tetrahydropyrimidine fungicides of the following formula. 
These types of compounds are not considered to be part of the present invention.
U.S. Pat. No. 5,854,234 depicts cyclic amidino nitric oxide synthase inhibitors of the following formula. 
Such compounds are not considered to be part of the present convention.
Duggan et al, J. Med. Chem. 2000, 43, 3736-3745, describe non-peptide, avb3 antagonists, an example of which is the following. 
Such compounds are not considered to be part of the present invention.
It is one object of the present invention to provide a novel amino acid.
It is another object of the present invention to provide a novel method of making a novel amino acid.
It is another object of the present invention to provide a novel method of using a novel amino acid.
It is another object of the present invention to provide novel acyclic and cyclic peptides comprising a novel amino acid, wherein the peptides bind to a novel biological receptor.
It is another object of the present invention to provide novel pharmaceuticals comprising a targeting moiety that binds to a biological receptor, an optional linking group, and a therapeutically effective radioisotope or diagnostically effective imageable moiety, wherein the targeting moiety is an acyclic or cyclic peptide comprising a novel amino acid.
These and other objects, which will become apparent during the following detailed description, have been achieved by the inventors"" discovery that the amino acid of formula I: 
is an effective arginine mimic.
Thus, in an embodiment, the present invention provides a novel compound of formula I: 
or a stereoisomer or salt form thereof, wherein:
R1 is H or a hydroxy protecting group;
alternatively, OR1 is an activated ester;
R2 is H, CH3, or an amine protecting group;
R2a is H or an amine protecting group;
R3 is H or an amine protecting group;
R4 is H or an amine protecting group; and,
R4a is H or an amine protecting group;
provided that one of R1, R2, R2a, R3, R4, and R4 is other than H.
In another embodiment, the present invention provides a novel compound of formula Ia or Ib: 
or a stereoisomer or salt form thereof.
In another preferred embodiment, the present invention provides a compound of formula I, wherein:
R1 is selected from H, OMe, OEt, OBzl, Oallyl, and Ot-Bu;
alternatively, OR1 is selected from OSu, OBt, OPfp, and Onp;
R2 is Fmoc or Boc
R2a is H;
R3 is H;
R4 is selected from Tos, Mtr, Pbf, Mts, Pmc, Boc, Mbs, NO2, and Cbz;
R4a is H;
alternatively, when R4 Boc, R4 is Boc; and,
alternatively, when R4 Cbz, R4a is Cbz;
In a more preferred embodiment, the compound of I is selected from:
Fmoc-cyArg(Tos)-OH, Fmoc-cyArg(Mtr)-OH, Fmoc-cyArg(Pbf)-OH, Fmoc-cyArg(Mts)-OH, Fmoc-cyArg(Pmc)-OH, Fmoc-cyArg(Boc)2-OH, Boc-cyArg(Mbs)-OH, Boc-cyArg(Boc)2-OH, Boc-cyArg(Mtr)-OH, Boc-cyArg(NO2)-OH, Boc-cyArg(Pbf)-OH, Boc-cyArg(Pmc)-OH, Boc-cyArg(Tos)-OH, and Boc-cyArg(Cbz)2-OH;
wherein cyArg corresponds to the unmodified amino acid.
In another embodiment, the present invention provides a novel process for making a compound of formula I: 
the process comprising: reducing a pyrimidine of formula II to form a compound of formula I.
In a preferred embodiment, reduction is performed by contacting the compound of formula II with trifluoroacetic acid and a trialkylsilane. One of ordinary skill in the art would recognize that a number of trialkylsilanes could be used for this reduction, including trimethylsilane, triethylsilane, and triisopropylsilane. Alternatively, the reduction is performed via catalytic hydrogenation.
In a more preferred embodiment, the trialkylsilane is triisopropylsilane.
A method of preparing an arginine-containing peptide, comprising: synthesizing the peptide using a compound of formula I in place of arginine or protected arginine: 
or a stereoisomer or salt form thereof, wherein:
R1 is H or a hydroxy protecting group;
alternatively, OR1 is an activated ester;
R2 is H or an amine protecting group;
R2a is H or an amine protecting group;
R3is H or an amine protecting group;
R4 is H or an amine protecting group; and,
R4a is H or an amine protecting group;
provided that one of R1, R2, R2a, R3, R4, and R4 is other than H.
In another embodiment, the present invention provides a novel compound, comprising: an acyclic or cyclic peptide that targets a biological receptor, wherein the peptide comprises an arginine mimic of formula IIIa or IIIb: 
In another preferred embodiment, the biological receptor is selected from the group: Tuftsin, Thrombin catalytic site, Thrombin exosite, Factor XIIIa, Factor Xa, Factor IXa, Factor VIIa, Neurotensin, Bombesin, the Bradykinin receptors, and an intergrin selected avb3, aIIbb3, avb5, a5b1, a2b1, a1b1, and Mac-1
In a more preferred embodiment, the biological receptor is selected from the group: Tuftsin, Thrombin catalytic site, Thrombin exosite, Factor XIIIa, Factor Xa, Factor IXa, Factor VIIa, and an intergrin selected from avb3, aIIbb3, avb5, a5b1, a2b1, a1b1, and Mac-1
In another more preferred embodiment, the peptide comprises an RGD, TKPR, or TKPPR segment wherein arginine has been replaced by the arginine mimic of formula III.
In an even more preferred embodiment, the compound further comprises: a chelator and 0-1 linking groups between the peptide and the chelator.
In a still more preferred embodiment, the linking group is present.
In another embodiment, the present invention provides a novel compound, comprising: a cyclic peptide that targets a biological receptor, a chelator, and a linking group between the chelator and peptide, wherein the receptor is the integrin xcex1vxcex23 and the compound is of the formula:
(Q)dxe2x80x94Lnxe2x80x94Ch or (Q)dxe2x80x94Lnxe2x80x94(Ch)d,
wherein, Q is a peptide independently selected from the group: 
K is a group of formula IIIa or IIIb: 
Kxe2x80x2 is a group of formula IIIc or IIIc: 
L is independently selected at each occurrence from the group: glycine, L-alanine, and D-alanine;
M is L-aspartic acid;
Mxe2x80x2 is D-aspartic acid;
R1 is an amino acid substituted with 0-1 bonds to Ln, independently selected at each occurrence from the group: glycine, L-valine, D-valine, alanine, leucine, isoleucine, norleucine, 2-aminobutyric acid, 2-aminohexanoic acid, tyrosine, phenylalanine, thienylalanine, phenylglycine, cyclohexylalanine, homophenylalanine, 1-naphthylalanine, lysine, serine, ornithine, 1,2-diaminobutyric acid, 1,2-diaminopropionic acid, cysteine, penicillamine, and methionine;
R2 is an amino acid, substituted with 0-1 bonds to Ln, independently selected at each occurrence from the group: glycine, valine, alanine, leucine, isoleucine, norleucine, 2-aminobutyric acid, 2-aminohexanoic acid, tyrosine, L-phenylalanine, D-phenylalanine, thienylalanine, phenylglycine, biphenylglycine, cyclohexylalanine, homophenylalanine, L-1-naphthylalanine, D-1-naphthylalanine, lysine, serine, ornithine, 1,2-diaminobutyric acid, 1,2-diaminopropionic acid, cysteine, penicillamine, methionine, and 2-aminothiazole-4-acetic acid;
R3 is an amino acid, substituted with 0-1 bonds to Ln, independently selected at each occurrence from the group: glycine, D-valine, D-alanine, D-leucine, D-isoleucine, D-norleucine, D-2-aminobutyric acid, D-2-aminohexanoic acid, D-tyrosine, D-phenylalanine, D-thienylalanine, D-phenylglycine, D-cyclohexylalanine, D-homophenylalanine, D-1-naphthylalanine, D-lysine, D-serine, D-ornithine, D-1,2-diaminobutyric acid, D-1,2-diaminopropionic acid, D-cysteine, D-penicillamine, and D-methionine;
R4 is an amino acid, substituted with 0-1 bonds to Ln, independently selected at each occurrence from the group: glycine, D-valine, D-alanine, D-leucine, D-isoleucine, D-norleucine, D-2-aminobutyric acid, D-2-aminohexanoic acid, D-tyrosine, D-phenylalanine, D-thienylalanine, D-phenylglycine, D-cyclohexylalanine, D-homophenylalanine, D-1-naphthylalanine, D-lysine, D-serine, D-ornithine, D-1,2-diaminobutyric acid, D-1,2-diaminopropionic acid, D-cysteine, D-penicillamine, D-methionine, and 2-aminothiazole-4-acetic acid;
R5 is an amino acid, substituted with 0-1 bonds to Ln, independently selected at each occurrence from the group: glycine, L-valine, L-alanine, L-leucine, L-isoleucine, L-norleucine, L-2-aminobutyric acid, L-2-aminohexanoic acid, L-tyrosine, L-phenylalanine, L-thienylalanine, L-phenylglycine, L-cyclohexylalanine, L-homophenylalanine, L-1-naphthylalanine, L-lysine, L-serine, L-ornithine, L-1,2-diaminobutyric acid, L-1,2-diaminopropionic acid, L-cysteine, L-penicillamine, L-methionine, and 2-aminothiazole-4-acetic acid;
provided that one of R1, R2, R3, R4, and R5 in each Q is substituted with a bond to Ln, further provided that when R2 is 2-aminothiazole-4-acetic acid, K is N-methylarginine, further provided that when R4 is 2-aminothiazole-4-acetic acid, K and Kxe2x80x2 are N-methylarginine, and still further provided that when R5 is 2-aminothiazole-4-acetic acid, Kxe2x80x2 is N-methylarginine;
d is selected from 1, 2, 3, and 4;
Ln is a linking group having the formula:
(CR6R7)gxe2x80x94(W)hxe2x80x94(CR6aR7a)gxe2x80x2, xe2x80x94(Z)kxe2x80x94(W)hxe2x80x2xe2x80x94(CR8R9)gxe2x80x3xe2x80x94(W)hxe2x80x3xe2x80x94(CR8aR9a)gxe2x80x3xe2x80x2
provided that g+h+gxe2x80x2+k+hxe2x80x2+gxe2x80x3+hxe2x80x3+gxe2x80x3xe2x80x2 is other than 0;
W is independently selected at each occurrence from the group: O, S, NH, NHC(xe2x95x90O), C(xe2x95x90O)NH, C(xe2x95x90O), C(xe2x95x90O)O, OC(xe2x95x90O), NHC(xe2x95x90S)NH, NHC(xe2x95x90O)NH, SO2, (OCH2CH2)s, (CH2CH2O)sxe2x80x2, (OCH2CH2CH2)sxe2x80x2, (CH2CH2CH2O)t, and (aa)txe2x80x2;
aa is, independently at each occurrence, an amino acid;
Z is selected from the group: aryl substituted with 0-3 R10, C3-10 cycloalkyl substituted with 0-3 R10, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R10;
R6, R6a, R7, R7a, R8, R8a, R9 and R9a are independently selected at each occurrence from the group: H, xe2x95x90O, COOH, SO3H, PO3H, C1-C5 alkyl substituted with 0-3 R10, aryl substituted with 0-3 R10, benzyl substituted with 0-3 R10, and C1-C5 alkoxy substituted with 0-3 R10, NHC(xe2x95x90O)R11, C(xe2x95x90O)NHR11, NHC(xe2x95x90O)NHR11, NHR11, R11, and a bond to Ch;
R10 is independently selected at each occurrence from the group: a bond to Ch, COOR11, OH, NHR11, SO3H, PO3H, aryl substituted with 0-3 R11, C1-5 alkyl substituted with 0-1 R12, C1-5 alkoxy substituted with 0-1 R12, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R11;
R11 is independently selected at each occurrence from the group: H, aryl substituted with 0-1 R12, a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-1 R12, C3-10 cycloalkyl substituted with 0-1 R12, polyalkylene glycol substituted with 0-1 R12, carbohydrate substituted with 0-1 R12, cyclodextrin substituted with 0-1 R12, amino acid substituted with 0-1 R12, polycarboxyalkyl substituted with 0-1 R12, polyazaalkyl substituted with 0-1 R12, peptide substituted with 0-1 R12, wherein the peptide is comprised of 2-10 amino acids, and a bond to Ch;
R12 is a bond to Ch;
k is selected from 0, 1, and 2;
h is selected from 0, 1, and 2;
hxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
hxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
g is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x3 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
s is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
sxe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
sxe2x80x3 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
t is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
txe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
Ch is a metal bonding unit having a formula selected from the group: 
A1, A2, A3, A4, A5, A6, A7, and A8 are independently selected at each occurrence from the group: N, NR13, NR13R14, S, SH, S(Pg), O, OH, PR13, PR13R14, P(O)R15R16, and a bond to Ln;
E is a bond, CH, or a spacer group independently selected at each occurrence from the group: C1-C10 alkyl substituted with 0-3 R17, aryl substituted with 0-3 R17, C3-10 cycloalkyl substituted with 0-3 R17, heterocyclo-C1-10 alkyl substituted with 0-3 R17, wherein the heterocyclo group is a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O, C6-10 aryl-C1-10 alkyl substituted with 0-3 R17, C1-10 alkyl-C6-10 aryl-substituted with 0-3,R17, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R17;
R13, and R14 are each independently selected from the group: a bond to Ln, hydrogen, C1-C10 alkyl substituted with 0-3 R17, aryl substituted with 0-3 R17, C1-10 cycloalkyl substituted with 0-3 R17, heterocyclo-C1-10 alkyl substituted with 0-3 R17, wherein the heterocyclo group is a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O, C6-10 aryl-C1-10 alkyl substituted with 0-3 R17, C1-10 alkyl-C6-10 aryl-substituted with 0-3 R17, a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R17, and an electron, provided that when one of R13 or R14 is an electron, then the other is also an electron;
alternatively, R13 and R14 combine to form xe2x95x90C(R20)(R21);
R15 and R16 are each independently selected from the group: a bond to Ln, xe2x80x94OH, C1-C10 alkyl substituted with 0-3 R17, C1-C10 alkyl substituted with 0-3 R17, aryl substituted with 0-3 R17, C3-10 cycloalkyl substituted with 0-3 R17, heterocyclo-C1-10 alkyl substituted with 0-3 R17, wherein the heterocyclo group is a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O, C6-10 aryl-C1-10 alkyl substituted with 0-3 R17, C1-10 alkyl-C6-10 aryl-substituted with 0-3 R17, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R17;
R17 is independently selected at each occurrence from the group: a bond to Ln, xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R18, xe2x80x94C(xe2x95x90O)R18, xe2x80x94C(xe2x95x90O)N(R18)2, xe2x80x94CHO, xe2x80x94CH2OR18, xe2x80x94OC(xe2x95x90O)R18, xe2x80x94OC(xe2x95x90O)OR18a, xe2x80x94OR18, xe2x80x94OC(xe2x95x90O)N(R18)2, xe2x80x94NR19C(xe2x95x90O)R18, xe2x80x94NR19C(xe2x95x90O)OR18a, xe2x80x94NR19C(xe2x95x90O)N(R18)2, xe2x80x94NR19SO2N(R18)2, xe2x80x94NR19SO2R18a, xe2x80x94SO3H, xe2x80x94SO2R18a, xe2x80x94SR18, xe2x80x94S(xe2x95x90O)R18a, xe2x80x94SO2N(R18)2, xe2x80x94N(R18)2, xe2x80x94NHC(xe2x95x90S)NHR18, xe2x95x90NOR18, NO2, xe2x80x94C(xe2x95x90O)NHOR18, xe2x80x94C(xe2x95x90O)NHNR18R18a, xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, C1-C5 alkyl, C2-C4 alkenyl, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, C2-C6 alkoxyalkyl, aryl substituted with 0-2 R18, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O;
R18, R18a, and R19 are independently selected at each occurrence from the group: a bond to Ln, H, C1-C6 alkyl, phenyl, benzyl, C1-C6,alkoxy, halide, nitro, cyano, and trifluoromethyl;
Pg is a thiol protecting group;
R20 and R21 are independently selected from the group: H, C1-C10 alkyl, xe2x80x94CN, xe2x80x94CO2R25, xe2x80x94C(xe2x95x90O)R25, xe2x80x94C(xe2x95x90O)N(R25)2, C2-C10 1-alkene substituted with 0-3 R23, C2-C10 1-alkyne substituted with 0-3 R23, aryl substituted with 0-3 R23, unsaturated 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R23, and unsaturated C3-10 carbocycle substituted with 0-3 R23;
alternatively, R20 and R21, taken together with the divalent carbon radical to which they are attached form: 
R22 and R23 are independently selected from the group: H, R24, C1-C10 alkyl substituted with 0-3 R24, C2-C10 alkenyl substituted with 0-3 R24, C2-C10 alkynyl substituted with 0-3 R24, aryl substituted with 0-3 R24, a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R24, and C3-10 carbocycle substituted with 0-3 R24;
alternatively, R22, R23 taken together form a fused aromatic or a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O;
a and b indicate the positions of optional double bonds and n is 0 or 1;
R24 is independently selected at each occurrence from the group: xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R25, xe2x80x94C(xe2x95x90O)R25, xe2x80x94C(xe2x95x90O)N(R25)2, xe2x80x94N(R25)3+, xe2x80x94CH2OR25, xe2x80x94OC(xe2x95x90O)R25, xe2x80x94OC(xe2x95x90O)OR25a, xe2x80x94OR25, xe2x80x94OC(xe2x95x90O)N(R25)2, xe2x80x94NR26C (xe2x95x90O)R25, xe2x80x94NR26C(xe2x95x90O)OR25a, xe2x80x94NR26C(xe2x95x90O)N(R25)2, xe2x80x94NR26SO2N(R25)2, xe2x80x94NR26SO2R25a, xe2x80x94SO3H, xe2x80x94SO2R25a, xe2x80x94SR25, xe2x80x94S(xe2x95x90O)R25a, xe2x80x94SO2N(R25)2, xe2x80x94N(R25)2, xe2x95x90NOR25, xe2x80x94C(xe2x95x90O)NHOR25, xe2x80x94OCH2CO2H, and 2-(1-morpholino)ethoxy; and,
R25, R25a, and R26 are each independently selected at each occurrence from the group: hydrogen and C1-C6 alkyl;
and a pharmaceutically acceptable salt thereof.
In a still more preferred embodiment, the present invention provides a compound, wherein:
Q is a peptide selected from the group: 
L is glycine;
M is L-aspartic acid;
Mxe2x80x2 is D-aspartic acid;
R1 is L-valine, D-valine, D-lysine optionally substituted on the xcex5 amino group with a bond to Ln or L-lysine optionally substituted on the xcex5 amino group with a bond to Ln;
R2 is L-phenylalanine, D-phenylalanine, D-1-naphthylalanine, 2-aminothiazole-4-acetic acid, L-lysine optionally substituted on the e amino group with a bond to Ln or tyrosine, the tyrosine optionally substituted on the hydroxy group with a bond to Ln;
R3 is D-valine, D-phenylalanine, or L-lysine optionally substituted on the xcex5 amino group with a bond to Ln;
R4 is D-phenylalanine, D-tyrosine substituted on the hydroxy group with a bond to Ln, or L-lysine optionally substituted on the xcex5 amino group with a bond to Ln;
provided that one of R1 and R2 in each Q is substituted with a bond to Ln, and further provided that when R2 is 2-aminothiazole-4-acetic acid, K is N-methylarginine;
d is 1 or 2;
W is independently selected at each occurrence from the group: NHC(xe2x95x90O), C(xe2x95x90O)NH, C(xe2x95x90O), (CH2CH2O)sxe2x80x2, and (CH2CH2CH2O)t;
R6, R6a, R7, R7a, R8, R8a, R9, and R9a are independently selected at each occurrence from the group: H, NHC(xe2x95x90O)R11, and a bond to Ch;
k is 0;
hxe2x80x3, is selected from 0, 1, 2, and 3;
g is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
sxe2x80x2 is 1 or 2;
t is 1 or 2;
Ch is 
A1 is selected from the group: OH, and a bond to Ln;
A2, A4, and A6 are each N;
A3, A5, and A8 are each OH;
A7 is a bond to Ln or NH-bond to Ln;
E is a C2 alkyl substituted with 0-1 R17;
R17 is xe2x95x90O;
alternatively, Ch is 
A1 is NH2 or Nxe2x95x90C(R20)(R21);
E is a bond;
A2 is NHR13;
xe2x80x83R13 is a heterocycle substituted with R17, the heterocycle being selected from pyridine and pyrimidine;
R17 is selected from a bond to Ln, C(xe2x95x90O)NHR18, and C(xe2x95x90O)R18;
xe2x80x83R18 is a bond to Ln;
xe2x80x83R24 is selected from the group: xe2x80x94CO2R25, xe2x80x94OR25, xe2x80x94SO3H, and xe2x80x94N(R25)2;
R25 is independently selected at each occurrence from the group: hydrogen and methyl;
alternatively, Ch is 
A1, A2, A3, and A4 are each N;
A5, A6, and A8 are each OH;
A7 is a bond to Ln;
E is a C2 alkyl substituted with 0-1 R17; and,
R17 is xe2x95x90O.
In another embodiment, the present invention provides compounds of the formulas Ia and Ib:
(QLn)dChxe2x80x83xe2x80x83(Ia);
(Q)dxe2x80x2Lnxe2x80x94Chxe2x80x83xe2x80x83(Ib)
wherein, d is 1-3, dxe2x80x2 is 2-4, Ln is a linking group, Ch is a metal chelator, and Q is a compound of formula IV or IVa: 
or a pharmaceutically acceptable salt or prodrug form thereof, wherein:
R31 is a C6-C14 saturated, partially saturated, or aromatic carbocyclic ring system, substituted with 0-4 R10 or R10a, and optionally bearing a bond to Ln; a heterocyclic ring system, optionally substituted with 0-4 R10 or R10a, and optionally bearing a bond to Ln;
R32 is selected from: xe2x80x94C(xe2x95x90O)xe2x80x94; xe2x80x94C(xe2x95x90S)xe2x80x94; xe2x80x94S(xe2x95x90O)2xe2x80x94; xe2x80x94S(xe2x95x90O)xe2x80x94; and xe2x80x94P(xe2x95x90Z)(ZR13)xe2x80x94;
Z is S or O;
nxe2x80x3 and nxe2x80x2 are independently 0-2;
R1 and R22 are independently selected from the following groups: H, xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R13, xe2x80x94C(xe2x95x90O)R13, xe2x80x94C(xe2x95x90O)N(R13)2, xe2x80x94CHO, xe2x80x94CH2OR13, xe2x80x94OC(xe2x95x90O)R13, xe2x80x94OC(xe2x95x90O)OR13a, xe2x80x94OR13, xe2x80x94OC(xe2x95x90O)N(R13)2, xe2x80x94NR13C(xe2x95x90O)R13, xe2x80x94NR14C(xe2x95x90O)OR13a, xe2x80x94NR13C(xe2x95x90O)N(R13)2, xe2x80x94NR14SO2N(R13)2, xe2x80x94NR14SO2R13a, xe2x80x94SO3H, xe2x80x94SO2R13a, xe2x80x94SR13, xe2x80x94S(xe2x95x90O)R13a, xe2x80x94SO2N(R13)2, xe2x80x94N(R13)2, xe2x80x94NHC(xe2x95x90NH)NHR13, xe2x80x94C(xe2x95x90NH)NHR13, xe2x95x90NOR13, NO2, xe2x80x94C(xe2x95x90O)NHOR13, xe2x80x94C(xe2x95x90O)NHNR13R13a, xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, C1-C8 alkyl substituted with 0-2 R11; C2-C8 alkenyl substituted with 0-2 R11; C2-C8 alkynyl substituted with 0-2 R11; C3-C10 cycloalkyl substituted with 0-2 R11; a bond to Ln; aryl substituted with 0-2 R12; and a 5-10-membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O, said heterocyclic ring being substituted with 0-2 R12;
R1 and R21 can alternatively join to form a 3-7 membered carbocyclic ring substituted with 0-2 R12;
when nxe2x80x2 is 2, R1 or R21 can alternatively be taken together with R1 or R21 on an adjacent carbon atom to form a direct bond, thereby to form a double or triple bond between said carbon atoms;
R21 and R23 are independently selected from: hydrogen; C1-C4 alkyl, optionally substituted with 1-6 halogen; and benzyl;
R22 and R23 can alternatively join to form a 3-7 membered carbocyclic ring substituted with 0-2 R12;
when nxe2x80x3 is 2, R22 or R23 can alternatively be taken together with R22 or R23 on an adjacent carbon atom to form a direct bond, thereby to form a double or triple bond between the adjacent carbon atoms;
R1 and R2, where R21 is H, can alternatively join to form a 5-8 membered carbocyclic ring substituted with 0-2 R12;
R11 is selected from one or more of the following: xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R13, xe2x80x94C(xe2x95x90O)R13, xe2x80x94C(xe2x95x90O)N(R13)2, xe2x80x94CHO, xe2x80x94CH2OR13, xe2x80x94OC(xe2x95x90O)R13, xe2x80x94OC(xe2x95x90O)OR13a, xe2x80x94OR13, xe2x80x94OC(xe2x95x90O)N(R13)2, xe2x80x94NR13C(xe2x95x90O)R13, xe2x80x94NR14C(xe2x95x90O)OR13a, xe2x80x94NR13C(xe2x95x90O)N(R13)2, xe2x80x94NR14SO2N(R13)2, xe2x80x94NR14SO2R13a, xe2x80x94SO3H, xe2x80x94SO2R13a, xe2x80x94SR13, xe2x80x94S(xe2x95x90O)R13a, xe2x80x94SO2N(R13)2, xe2x80x94N(R13)2, xe2x80x94NHC(xe2x95x90NH)NHR13, xe2x80x94C(xe2x95x90NH)NHR13, xe2x95x90NOR13, NO2, xe2x80x94C(xe2x95x90O)NHOR13, xe2x80x94C(xe2x95x90O)NHNR13R13a, xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, C1-C5 alkyl, C2-C4 alkenyl, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, C2-C6 alkoxyalkyl, C3-C6 cycloalkoxy, C1-C4 alkyl (alkyl being substituted with 1-5 groups selected independently from: xe2x80x94NR13R14, xe2x80x94CF3, NO2, xe2x80x94SO2R13a, or xe2x80x94S(xe2x95x90O)R13a), aryl substituted with 0-2 R12, and a 5-10-membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O, said heterocyclic ring being substituted with 0-2 R12;
R12 is selected from one or more of the following: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C1-C5 alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, C7-C10 arylalkyl, C1-C5 alkoxy, xe2x80x94CO2R13, xe2x80x94C(xe2x95x90O)NHOR13a, xe2x80x94C(xe2x95x90O)NHN(R13)2, xe2x95x90NOR13, xe2x80x94B(R34)(R35), C3-C6 cycloalkoxy, xe2x80x94OC(xe2x95x90O)R13, xe2x80x94C(xe2x95x90O)R13, xe2x80x94OC(xe2x95x90O)OR13a, xe2x80x94OR13, xe2x80x94(C1-C4 alkyl)-OR13, xe2x80x94N(R13)2, xe2x80x94OC(xe2x95x90O)N(R13)2, xe2x80x94NR13C(xe2x95x90O)R13, xe2x80x94NR13C(xe2x95x90O)OR13a, xe2x80x94NR13C(xe2x95x90O)N(R13)2, xe2x80x94NR13SO2N(R13)2, xe2x80x94NR13SO2R13a, xe2x80x94SO3H, SO2R13a, xe2x80x94S(xe2x95x90O)R13a, xe2x80x94SR13, xe2x80x94SO2N(R13)2, C2-C6 alkoxyalkyl, methylenedioxy, ethylenedioxy, C1-C4 haloalkyl, C1-C4 haloalkoxy, C1-C4 alkylcarbonyloxy, C1-C4 alkylcarbonyl, C1-C4 alkylcarbonylamino, xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, and C1-C4 alkyl (alkyl being substituted with xe2x80x94N(R13)2, xe2x80x94CF3, NO2, or xe2x80x94S(xe2x95x90O) R13a);
R13 is selected independently from: H, C1-C10 alkyl, C3-C10 cycloalkyl, C4-C12 alkylcycloalkyl, aryl, xe2x80x94(C1-C10 alkyl)aryl, and C3-C10 alkoxyalkyl;
R13a is C1-C10 alkyl, C3-C10 cycloalkyl, C4-C12 alkylcycloalkyl, aryl, xe2x80x94(C1-C10 alkyl)aryl, or C3-C10 alkoxyalkyl;
when two R13 groups are bonded to a single N, said R13 groups may alternatively be taken together to form xe2x80x94(CH2)2-5xe2x80x94or xe2x80x94(CH2)O(CH2)xe2x80x94;
R14 is OH, H, C1-C4 alkyl, or benzyl;
R2 is H or C1-C8 alkyl;
R10 and R10a are selected independently from one or more of the following: phenyl, benzyl, phenethyl, phenoxy, benzyloxy, halogen, hydroxy, nitro, cyano, C1-C5 alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, C7-C10 arylalkyl, C1-C5 alkoxy, xe2x80x94CO2R13, xe2x80x94C(xe2x95x90O)N(R13)2, xe2x80x94C(xe2x95x90O)NHOR13a, xe2x80x94C(xe2x95x90O)NHN(R13)2, xe2x95x90NOR13, xe2x80x94B(R34)(R35), C3-C6 cycloalkoxy, xe2x80x94OC(xe2x95x90O)R13, xe2x80x94C(xe2x95x90O)R13, xe2x80x94OC(xe2x95x90O)OR13a, xe2x80x94OR13, xe2x80x94(C1-C4 alkyl)-OR13, xe2x80x94N(R13)2, xe2x80x94OC(xe2x95x90O)N(R13)2, xe2x80x94NR13C(xe2x95x90O)R13, xe2x80x94NR13C(xe2x95x90O)OR13a, xe2x80x94NR13C(xe2x95x90O)N(R13)2, xe2x80x94NR13SO2N(R13)2, xe2x80x94NR13SO2R13a, xe2x80x94SO3H, xe2x80x94SO2R13a, xe2x80x94S(xe2x95x90O)R13a, xe2x80x94SR13, xe2x80x94SO2N(R13)2, C2-C6 alkoxyalkyl, methylenedioxy, ethylenedioxy, C1-C4 haloalkyl (including xe2x80x94CvFw where v=1 to 3 and w=1 to (2v+1)), C1-C4 haloalkoxy, C1-C4 alkylcarbonyloxy, C1-C4 alkylcarbonyl, C1-C4 alkylcarbonylamino, xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, and C1-C4 alkyl (alkyl being substituted with xe2x80x94N(R13)2, xe2x80x94CF3, NO2, or xe2x80x94S(xe2x95x90O)R13a);
J is xcex2-Ala or an L-isomer or D-isomer amino acid of structure xe2x80x94N(R3)C(R4)(R5)C(xe2x95x90O)xe2x80x94, wherein:
R3 is H or C1-C8 alkyl;
R4 is H or C1-C3 alkyl;
R5 is selected from: H, xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R13, xe2x80x94C(xe2x95x90O)R13, xe2x80x94C(xe2x95x90O)N(R13)2, xe2x80x94CHO, xe2x80x94CH2OR13, xe2x80x94OC(xe2x95x90O)R13, OC(xe2x95x90O)OR13a, xe2x80x94OR13, xe2x80x94OC(xe2x95x90O)N(R13)2, xe2x80x94NR13C(xe2x95x90O)R13, xe2x80x94NR14C(xe2x95x90O)OR13a, xe2x80x94NR13C(xe2x95x90O)N(R13)2, xe2x80x94NR14SO2N(R13)2, xe2x80x94NR14SO2R13a, xe2x80x94SO3H, xe2x80x94SO2R13a, xe2x80x94SR13, xe2x80x94S(xe2x95x90O)R13a, xe2x80x94SO2N(R13)2, xe2x80x94N(R13)2, xe2x80x94NHC(xe2x95x90NH)NHR13, xe2x80x94C(xe2x95x90NH)NHR13, xe2x95x90NOR13, NO2, xe2x80x94C(xe2x95x90O)NHOR13, xe2x80x94C(xe2x95x90O)NHNR13R13a, xe2x95x90NOR13, xe2x80x94B(R34)(R35), xe2x80x94OCH2CO2H, 2-(1-morpholino)ethoxy, xe2x80x94SC(xe2x95x90NH)NHR13, N3, xe2x80x94Si(CH3)3, (C1-C5 alkyl)NHR16C1-C8 alkyl substituted with 0-2 R11; C2-C8 alkenyl substituted with 0-2 R11; C2-C10 alkynyl substituted with 0-2 R11; C3-C10 cycloalkyl substituted with 0-2 R11; a bond to Ln; aryl substituted with 0-2 R12; and a 5-10-membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, or O, said heterocyclic ring being substituted with 0-2 R12;
xe2x80x94(C0-C6 alkyl)X; 
where q is independently 0 or 1; 
xe2x80x94(CH2)mS(O)pxe2x80x2(CH2)2X, where m=1,2 and pxe2x80x2=0-2;
wherein X is defined below; and
R3 and R4 may also be taken together to form 
xe2x80x83where n is 0 or 1
and X is w 
R3 and R5 can alternatively be taken together to form xe2x80x94(CH2)txe2x80x94 or xe2x80x94CH2S(O)pxe2x80x2C(CH3)2xe2x80x94, where t=2-4 and pxe2x80x2=0-2; or
R4 and R5 can alternatively be taken together to form xe2x80x94(CH2)uxe2x80x94, where u=2-5;
R16 is selected from: an amine protecting group; 1-2 amino acids; and 1-2 amino acids substituted with an amine protecting group;
L is xe2x80x94Y(CH2)vC(xe2x95x90O)xe2x80x94, wherein:
Y is NH, N(C1-C3 alkyl), O, or S; and v=1 or 2;
M is a D-isomer or L-isomer amino acid of structure 
qxe2x80x2 is 0-2;
R17 is H, C1-C3 alkyl;
R4a is selected from: xe2x80x94CO2R13, xe2x80x94SO3R13, xe2x80x94SO2NHR14, xe2x80x94B(R34)(R35), xe2x80x94NHSO2CF3, xe2x80x94CONHNHSO2CF3, xe2x80x94PO(OR13)2, xe2x80x94PO(OR13)R13, xe2x80x94SO2NH-heteroaryl (said heteroaryl being 5-10-membered and having 1-4 heteroatoms selected independently from N, S, or O) , xe2x80x94SO2NH-heteroaryl (said heteroaryl being 5-10-membered and having 1-4 heteroatoms selected independently from N, S, or O), xe2x80x94SO2NHCOR13, xe2x80x94CONHSO2R13a, xe2x80x94CH2CONHSO2R13a, xe2x80x94NHSO2NHCOR13a, xe2x80x94NHCONHSO2R13a, and xe2x80x94SO2NHCONHR13;
R34 and R35 are independently selected from: xe2x80x94OH, xe2x80x94F, xe2x80x94N(R13)2, and C1-C8-alkoxy; and
R34 and R35 can alternatively be taken together form: a cyclic boron ester where said chain or ring contains from 2 to 20 carbon atoms and, optionally, 1-4 heteroatoms independently selected from N, S, or O; a divalent cyclic boron amide where said chain or ring contains from 2 to 20 carbon atoms and, optionally, 1-4 heteroatoms independently selected from N, S, or O; and a cyclic boron amide-ester where said chain or ring contains from 2 to 20 carbon atoms and, optionally, 1-4 heteroatoms independently selected from N, S, or O.
In another preferred embodiment, the present invention provides compounds of Formula V or Va: 
wherein:
the shown phenyl ring in formula (II) is optionally substituted with 0-3 R10, and may optionally bear a bond to Ln;
R10 is selected independently from: H, C1-C8 alkyl, phenyl, halogen, and C1-C4 alkoxy;
R1 is selected from H, C1-C4 alkyl, phenyl, benzyl, phenyl-(C1-C4)alkyl, and a bond to Ln;
R2 is H or methyl;
R13 is selected independently from: H, C1-C10 alkyl, C3-C10 cycloalkyl, C4-C12 alkylcycloalkyl, aryl, xe2x80x94(C1-C10 alkyl)aryl, and C3-C10 alkoxyalkyl;
R13a is selected from C1-C10 alkyl, C3-C10 cycloalkyl, C4-C12 alkylcycloalkyl, aryl, xe2x80x94(C1-C10 alkyl)aryl, and C3-C10 alkoxyalkyl;
when two R13 groups are bonded to a single N, the R13 groups alternatively are taken together to form xe2x80x94(CH2)2-5xe2x80x94 or xe2x80x94(CH2)O(CH2)xe2x80x94;
R14 is selected from OH, H, C1-C4 alkyl, and benzyl;
J is xcex2-Ala or an L-isomer or D-isomer amino acid of structure xe2x80x94N(R3)C(R4)(R5)C(xe2x95x90O)xe2x80x94, wherein:
R3 is H or CH3;
R4 is H or C1-C3 alkyl;
R5 is selected from H, C1-C8 alkyl, C3-C6 cycloalkyl, C3-C6 cycloalkylmethyl, C1-C6 cycloalkylethyl, phenyl, phenylmethyl, CH2OH, CH2SH, CH2OCH3, CH2SCH3, CH2CH2SCH3, (CH2)sNH2, xe2x80x94(CH2)sNHC(xe2x95x90NH)(NH2), and xe2x80x94(CH2)sNHR16, where s=3-5, or a bond to Ln;
R3 and R5 alternatively are taken together to form xe2x80x94CH2CH2CH2xe2x80x94;
R4 and R5 alternatively are taken together to form xe2x80x94(CH2)uxe2x80x94, where u=2-5;
R16 is selected from: an amine protecting group; 1-2 amino acids; or 1-2 amino acids substituted with an amine protecting group;
L is xe2x80x94Y(CH2)vC(xe2x95x90O)xe2x80x94, wherein:
Y is NH, O, or S; and v=1,2;
M is a D-isomer or L-isomer amino acid of structure 
qxe2x80x2 is 0-2;
R17 is H or C1-C3 alkyl;
R4a is selected from: xe2x80x94CO2R13, xe2x80x94SO3R13, xe2x80x94SO2NHR14, xe2x80x94B(R34)(R35), xe2x80x94NHSO2CF3, xe2x80x94CONHNHSO2CF3, xe2x80x94PO(OR13)2, xe2x80x94PO(OR13)R13, xe2x80x94SO2NH-heteroaryl (said heteroaryl being 5-10-membered and having 1-4 heteroatoms selected independently from N, S, or O), and xe2x80x94SO2NH-heteroaryl (the heteroaryl being 5-10-membered and having 1-4 heteroatoms selected independently from N, S, or O), xe2x80x94SO2NHCOR13, xe2x80x94CONHSO2R13a, xe2x80x94CH2CONHSO2R13a, xe2x80x94NHSO2NHCOR13a, xe2x80x94NHCONHSO2R13a, and xe2x80x94SO2NHCONHR13.
In another more preferred embodiment, the present invention provides compounds of Formula (V) wherein:
the phenyl ring in formula (V) bears a bond to Ln;
R1 and R2 are independently selected from H, methyl;
J is selected from D-Val, D-2-aminobutyric acid, D-Leu, D-Ala, Gly, D-Pro, D-Ser, D-Lys, xcex2-Ala, Pro, Phe, NMeGly, D-Nle, D-Phg, D-Ile, D-Phe, D-Tyr, Ala, Nxcex5-p-azidobenzoyl-D-Lys, Nxcex5-p-benzoylbenzoyl-D-Lys, Nxcex5-tryptophanyl-D-Lys, Nxcex5-o-benzylbenzoyl-D-Lys, Nxcex5-p-acetylbenzoyl-D-Lys, Nxcex5-dansyl-D-Lys, Nxcex5-glycyl-D-Lys, Nxcex5-glycyl-p-benzoylbenzoyl-D-Lys, Nxcex5-p-phenylbenzoyl-D-Lys, Nxcex5-m-benzoylbenzoyl-D-Lys, and Nxcex5-o-benzoylbenzoyl-D-Lys;
L is selected from Gly, xcex2-Ala, and Ala; and
M is selected from Asp, xcex1MeAsp, xcex2Measp, NMeAsp, and D-Asp.
In another preferred embodiment, Ch is selected from the group: 
wherein:
A1, A2, A3, A4, A5, A6, A7, and A8 are independently selected at each occurrence from the group: NR40R41, S, SH, S(Pg), and OH;
W is a bond, CH, or C1-C3 alkyl substituted with 0-3 R52;
Wa is a methylene group or a C3-C6 carbocycle;
R40, R41, R42, R43, and R44 are each independently selected from the group: a bond to Ln, hydrogen, C1-C10 alkyl substituted with 0-3 R52, and an electron, provided that when one of R40 or R41 is an electron, then the other is also an electron, and provided that when one of R42 or R43 is an electron, then the other is also an electron;
alternatively, R40 and R41 combine to form, xe2x95x90C(C1-C3 alkyl)(C1-C3 alkyl);
R52 is independently selected at each occurrence from the group: a bond to Ln, xe2x95x90O, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R53, xe2x80x94C(xe2x95x90O)R53, xe2x80x94C(xe2x95x90O)N(R53)2, xe2x80x94CHO, xe2x80x94CH2OR53, xe2x80x94OC(xe2x95x90O)R53, xe2x80x94OC(xe2x95x90O)OR53a, xe2x80x94OR53, xe2x80x94OC(xe2x95x90O)N(R53)2, xe2x80x94NR53C(xe2x95x90O)R53, xe2x80x94NR54C(xe2x95x90O)OR53a, xe2x80x94NR53C(xe2x95x90O)N(R53)2, xe2x80x94NR54SO2N(R53)2, xe2x80x94NR54SO2R53a, xe2x80x94SO3H, xe2x80x94SO2R53a, xe2x80x94SR53, xe2x80x94S(xe2x95x90O)R53a, xe2x80x94SO2N(R53)2, xe2x80x94N(R53)2, xe2x80x94NHC(xe2x95x90NH)NHR53, xe2x80x94C(xe2x95x90NH)NHR53, xe2x95x90NOR53, NO2, xe2x80x94C(xe2x95x90O)NHOR53, xe2x80x94C(xe2x95x90O)NHNR53R53a, xe2x80x94OCH2CO2H, and 2-(1-morpholino)ethoxy;
R53, R53a, and R54 are independently selected at each occurrence from the group: a bond to Ln, and C1-C6 alkyl.
In another more preferred embodiment, the present invention provides a compound of Formula VI:
(QLn)dCh,
wherein:
d is 1; and
Ch is: 
A1 and A4 are SH or SPg;
A2 and A3 are NR41;
W is independently selected from the group: CHR52, CH2CHR52, CH2CH2CHR52 and CHR52Cxe2x95x90O; and,
R41 and R52 are independently selected from hydrogen and a bond to Ln,
alternatively, Ch is: 
A1 is NH2 or Nxe2x95x90C(C1-C3 alkyl)(C1-C3 alkyl);
W is a bond; and,
A2 is NHR40, wherein R40 is heterocycle substituted with R52, wherein the heterocycle is selected from the group:
pyridine, pyrazine, proline, furan, thiofuran, thiazole, and diazine, and R52 is a bond to Ln.
In another more preferred embodiment, the present invention provides a compound of Formula VI, wherein
d is 1;
Ch is: 
A1 is NH2 or Nxe2x95x90C(C1-C3 alkyl)(C1-C3 alkyl);
W is a bond; and,
A2 is NHR40, wherein R40 is heterocycle substituted with R52, wherein the heterocycle is selected from pyridine and thiazole, and R52 is a bond to Ln.
In another preferred embodiment, Ln is:
a bond between Q and Ch; or,
M1xe2x80x94[Y1(CR55R56)h(Z1)hxe2x80x3Y2]hxe2x80x2xe2x80x94M2
xe2x80x83wherein:
M1 is xe2x80x94[(CH2)gZ1]gxe2x80x2xe2x80x94(CR55R56)gxe2x80x3xe2x80x94; 
M2 is xe2x80x94(CR55R56)gxe2x80x3xe2x80x94[Z1(CH2)g]gxe2x80x2xe2x80x94;
g is independently 0-10;
gxe2x80x2 is independently 0-1;
gxe2x80x3 is 0-10;
h is 0-10;
hxe2x80x2 is 0-10;
hxe2x80x3 is 0-1
Y1 and Y2, at each occurrence, are independently selected from: a bond, O, NR56, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)NHxe2x80x94, Cxe2x95x90NR56, S, SO, SO2, SO3, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S;
Z1 is independently selected at each occurrence from a C6-C14 saturated, partially saturated, or aromatic carbocyclic ring system, substituted with 0-4 R57; a heterocyclic ring system, optionally substituted with 0-4 R57;
R55 and R56 are independently selected at each occurrence from: hydrogen; C1-C10 alkyl substituted with 0-5 R57; and (C1-C10 alkyl)aryl wherein the aryl is substituted with 0-5 R57;
R57 is independently selected at each occurrence from the group: hydrogen, OH, NHR58, C(xe2x95x90O)R58, OC(xe2x95x90O)R58, OC(xe2x95x90O)OR58, C(xe2x95x90O)OR58, C(xe2x95x90O)NR58xe2x80x94, Cxe2x89xa1N, SR58, SOR58, SO2R58, NHC(xe2x95x90O)R58, NHC(=0)NHR58, NHC(xe2x95x90S)NHR58; or, alternatively, when attached to an additional molecule Q, R57 is independently selected at each occurrence from the group: O, NR58, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)Nxe2x80x94, Cxe2x95x90NR58, S, SO, SO2, SO3, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S; and,
R58 is independently selected at each occurrence from the group:hydrogen; C1-C6 alkyl; benzyl, and phenyl.
In another more preferred embodiment, Ln is:
xe2x80x94(CR55R56)gxe2x80x3xe2x80x94[Y1(CR55R56)hY2]hxe2x80x2xe2x80x94(CR55R56)gxe2x80x3xe2x80x94,
wherein:
gxe2x80x3 is 1-10;
h is 0-10;
hxe2x80x2 is 1-10;
Y1 and Y2, at each occurrence, are independently selected from: a bond, O, NR56, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)NHxe2x80x94, Cxe2x95x90NR56, S, SO, SO2, SO3, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S;
R55 and R56 are independently selected at each occurrence from: hydrogen; C1-C10 alkyl substituted with 0-5 R57; and (C1-C10 alkyl)aryl wherein the aryl is substituted with 0-5 R57;
R57 is independently selected at each occurrence from the group: hydrogen, OH, NHR58, C(xe2x95x90O)R58, OC(xe2x95x90O)R58, OC(xe2x95x90O)OR58, C(xe2x95x90O)OR58, C(xe2x95x90O)NR58xe2x80x94, Cxe2x89xa1N, SR58, SOR58, SO2R58, NHC(xe2x95x90O)R58, NHC(xe2x95x90O)NHR58, and NHC(xe2x95x90S)NHR58;
alternatively, when attached to an additional molecule Q, R57 is independently selected at each occurrence from the group: O, NR58, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)Nxe2x80x94, Cxe2x95x90NR58, S, SO, SO2, SO3, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S, and R57 is attached to an additional molecule Q; and,
R58 is independently selected at each occurrence from the group:hydrogen; C1-C6 alkyl; benzyl, and phenyl.
In another more preferred embodiment, Ln is:
xe2x80x94(CR55R56)gxe2x80x3xe2x80x94[Y1(CR55R56)hY2]hxe2x80x2xe2x80x94(CR55R56)gxe2x80x3xe2x80x94,
wherein:
gxe2x80x3 is 1-5;
h is 0-5;
hxe2x80x2 is 1-5;
Y1 and Y2, at each occurrence, are independently selected from: O, NR56, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)NHxe2x80x94, Cxe2x95x90NR56, S, SO, SO2, SO3, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S; and,
R55 and R56 are independently selected at each occurrence from: hydrogen; C1-C10 alkyl; and (C1-C10 alkyl)aryl
In another more preferred embodiment, Ln is:
xe2x80x94(CR55R56)gxe2x80x3xe2x80x94[Y1(CR55R56)hY2]hxe2x80x2xe2x80x94(CR55R56)gxe2x80x3xe2x80x94,
wherein:
gxe2x80x3 is 1-5;
h is 0-5;
hxe2x80x2 is 1-5;
Y1 and Y2, at each occurrence, are independently selected from: O, NR56, Cxe2x95x90O, C(xe2x95x90O)O, OC(xe2x95x90O)O, C(xe2x95x90O)NHxe2x80x94, Cxe2x95x90NR56, S, NHC(xe2x95x90O), (NH)2C(xe2x95x90O), and (NH)2Cxe2x95x90S; and,
R55 and R56 are each hydrogen.
In another embodiment, the present invention provides a novel compound of the formula:
Chxe2x80x94Lnxe2x80x94(X1X2X3X4X5)d,
wherein:
X1 is an amino acid independently selected from the group: threonine, serine, 3-hydroxyproline, and 4-hydroxyproline;
X2 is cyArg;
X3 and X4 are amino acids independently selected at each occurrence from the group: proline, and homoproline;
X5 is an amino acid independently selected from the group: lysine, ornithine, arginine, glutamine, and 2-amino-5-(2-imidazolin-2-ylamino)pentanoic acid;
d is selected from 1, 2, and 3;
Ln is a linking group having the formula:
(CR6R7)gxe2x80x94(W)hxe2x80x94(CR6aR7a)gxe2x80x2xe2x80x94(W)hxe2x80x2xe2x80x94(CR8R9)gxe2x80x3xe2x80x94(W)hxe2x80x3xe2x80x94(CR8aR9a)gxe2x80x3xe2x80x2xe2x80x94(W)hxe2x80x3xe2x80x2
W is independently selected at each occurrence from the group: O, NH, NHC(xe2x95x90O), C(xe2x95x90O)NH, C(xe2x95x90O), C(xe2x95x90O)O, and OC(xe2x95x90O);
R6, R6a, R7, R7a, R8, R8a, R9 and R9a are independently selected at each occurrence from the group: xe2x95x90O, COOH, SO3H, PO3H, C1-C5 alkyl substituted with 0-3 R10, aryl substituted with 0-3 R10, benzyl substituted with 0-3 R10, and C1-C5 alkoxy substituted with 0-3 R10, NHC(xe2x95x90O)R11, C(xe2x95x90O)NHR11, NHC(xe2x95x90O)NHR11, NHR11, R11, and a bond to Ch;
R10 is independently selected at each occurrence from the group: a bond to Ch, COOR11, OH, NHR11, SO3H, PO3H, aryl substituted with 0-3 R11, C1-5 alkyl substituted with 0-1 R12, C1-5 alkoxy substituted with 0-1 R12, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R11;
R11 is independently selected at each occurrence from the group: H, aryl substituted with 0-1 R12, a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-1 R12, C3-10 cycloalkyl substituted with 0-1 R12, and a bond to Ch;
R12 is a bond to Ch;
h is selected from 0, 1, 2, 3, 4, and 5;
hxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
hxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
hxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
g is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x3 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
gxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10;
Ch is a metal bonding unit having the formula:
R13R14Nxe2x80x94NR15R16;
wherein:
R13, and R14 are each independently selected from the group: hydrogen, aryl substituted with 0-3 R17, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R17;
R15 and R16 are both H, or combine to form xe2x95x90C(R20)(R21);
R17 is independently selected at each occurrence from the group: a bond to Ln, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R18, xe2x80x94C(xe2x95x90O)R18, xe2x80x94C(xe2x95x90O)N(R18)2, xe2x80x94CH2OR18, xe2x80x94OC(xe2x95x90O)R18, xe2x80x94OC(xe2x95x90O)OR18, xe2x80x94OR18, xe2x80x94SO2N(R18)2, C1-C5 alkyl, aryl substituted with 0-2 R18, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O;
R18 is independently selected at each occurrence from the group: a bond to Ln, H, C1-C6 alkyl, phenyl, and benzyl;
R25, R25a, and R26 are each independently selected at each occurrence from the group: hydrogen and C1-C6 alkyl;
and a pharmaceutically acceptable salt thereof.
In a preferred embodiment, the present invention provides a compound, wherein:
X1 is an amino acid independently selected from the group: threonine, and serine;
X2 is cyArg;
X5 is an amino acid independently selected from the group: lysine, 2-amino-5-(2-imidazolin-2-ylamino)pentanoic acid, and arginine;
W is independently selected at each occurrence from the group: O, N, NHC(xe2x95x90O), C(xe2x95x90O)NH, and C(xe2x95x90O);
R6, R6a, R7, R7a, R8, R8a, R9 and R9a are independently selected at each occurrence from the group: xe2x95x90O, COOH, SO3H, PO3H, C1-C5 alkyl substituted with 0-1 R10, aryl substituted with 0-1 R10, benzyl substituted with 0-1 R10, and C1-C5 alkoxy substituted with 0-1 R10, NHC(xe2x95x90O)R11, C(xe2x95x90O)NHR11, NHC(xe2x95x90O)NHR11, NHR11, R11, and a bond to Ch;
R10 is independently selected at each occurrence from the group: a bond to Ch, COOR11, OH, NHR11, SO3H, aryl substituted with 0-1 R11, C1-5 alkyl substituted with 0-1 R12, C1-5 alkoxy substituted with 0-1 R12, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R11;
R11 is independently selected at each occurrence from the group: H, aryl substituted with 0-1 R12, a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-1 R12, and a bond to Ch;
h is 0 or 1;
hxe2x80x2 is 0 or 1;
Ch is a metal bonding unit having the formula:
R13R14Nxe2x80x94NR15R16;
xe2x80x83wherein:
R17 is independently selected at each occurrence from the group: a bond to Ln, F, Cl, Br, I, xe2x80x94CF3, xe2x80x94CN, xe2x80x94CO2R18, xe2x80x94C(xe2x95x90O)R18, xe2x80x94C(xe2x95x90O)N(R18)2, xe2x80x94CH2OR18, xe2x80x94OC(xe2x95x90O)R18, xe2x80x94OC(xe2x95x90O)OR18, xe2x80x94OR18, and xe2x80x94SO2N(R18)2;
R18 is independently selected at each occurrence from the group: a bond to Ln, H, and C1-C6 alkyl;
R25 is independently selected at each occurrence from the group: hydrogen and C1-C3 alkyl;
In another more preferred embodiment, the present invention provides a compound, wherein:
X1 is threonine;
X2 is cyArg;
X5 is arginine;
d is 1 or 2;
W is independently selected at each occurrence from the group: NHC(xe2x95x90O), C(xe2x95x90O)NH, and C(xe2x95x90O);
R6, R6a, R7, R7a, R8, R8a, R9 and R9a are independently selected at each occurrence from the group: H benzyl substituted with 0-1 R10, and a bond to Ch;
R10 is OH;
hxe2x80x3 is 0 or 1;
hxe2x80x3xe2x80x2 is 0 or 1;
g is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
Ch is a metal bonding unit having the formula:
R13R14Nxe2x80x94NR15R16;
xe2x80x83wherein:
R13 is H;
R14 is a heterocyclic ring system substituted with R17, the heterocyclic ring system being selected from pyridine and pyrimidine;
R17 is xe2x80x94C(xe2x95x90O)NHR18;
R18 is a bond to Ln;
R25 is independently selected at each occurrence from the group: hydrogen and methyl.
In another preferred embodiment, the present invention provides a kit comprising a compound of the present invention and a container containing the compound.
In another embodiment, the present invention provides a novel diagnostic or therapeutic, an MRI contrast agent, or an X-ray contrast agent, comprising: a metal and a compound of the present invention, wherein:
when a diagnostic or therapeutic is present, the metal is, selected from: 99mTc, 95Tc, 111In, 62Cu, 64Cu, 67Ga, 68Ga, 186Re, 188Re, 153Sm, 166Ho, 177Lu, 149Pm, 90Y, 212Bi, 103Pd, 109Pd, 159Gd, 140La, 198Au, 199Au, 169Yb, 175Yb, 165Dy, 166Dy, 67Cu, 105Rh, 111Ag, and 192Ir;
when an MRI contrast agent is present, the metal is selected from: Gd(III), Dy(III), Fe(III), and Mn(II); and,
when an X-ray contrast agent is present, the metal is selected from: Re, Sm, Ho, Lu, Pm, Y, Bi, Pd, Gd, La, Au, Au, Yb, Dy, Cu, Rh, Ag, and Ir.
In another embodiment, the present invention provides a novel compound capable of being used in an ultrasound contrast composition, comprising: a targeting moiety and a surfactant and the compound has 0-1 linking groups between the targeting moiety and surfactant.
In another even more preferred embodiment, the compound is a targeting moiety of the present invention, wherein the xe2x80x94Lnxe2x80x94Ch group is replaced by a group of the formula:
xe2x80x94Lnxe2x80x94Sf
wherein:
Sf is a surfactant which is a lipid or a compound of the formula: 
A9 is OR27;
A10 is OR27;
R27 is C(xe2x95x90O)C1-15 alkyl;
E1 is C1-4 alkylene substituted with 1-3 R28;
R28 is independently selected at each occurrence from the group: R30, xe2x80x94PO3Hxe2x80x94R30, xe2x95x90O, xe2x80x94CO2R29, xe2x80x94C(xe2x95x90O)R29, xe2x80x94CH2OR29, xe2x80x94OR29, and C1-C5 alkyl;
R29 is independently selected at each occurrence from the group: R30, H, C1-C6 alkyl, phenyl, and benzyl;
R30 is a bond to Ln;
Ln is a linking group having the formula:
(CR6R7)gxe2x80x94(W)hxe2x80x94(CR6aR7a)gxe2x80x2xe2x80x94(Z)kxe2x80x94(W)hxe2x80x2xe2x80x94(CR8R9)gxe2x80x3xe2x80x94(W)hxe2x80x3xe2x80x94(CR8aR9a)gxe2x80x3xe2x80x2
W is independently selected at each occurrence from the group: O, S, NH, NHC(xe2x95x90O), C(xe2x95x90O)NH, C(xe2x95x90O), C(xe2x95x90O)O, OC(xe2x95x90O), NHC(xe2x95x90S)NH, NHC(xe2x95x90O)NH, SO2, (OCH2CH2)20-200, (CH2CH2O)20-200, (OCH2CH2CH2)20-200, (CH2CH2CH2O)20-200, and (aa)txe2x80x2;
aa is independently at each occurrence an amino acid;
Z is selected from the group: aryl substituted with 0-3 R10, C3-10 cycloalkyl substituted with 0-3 R10, and a 5-10 membered heterocyclic ring system containing 1-4 heteroatoms independently selected from N, S, and O and substituted with 0-3 R10;
R6, R6a, R7, R7a, R8, R8a, R9 and R9a are independently selected at each occurrence from the group: H, xe2x95x90O, C1-C5 alkyl substituted with 0-3 R10, and C1-C5 alkoxy substituted with 0-3 R10, and a bond to Sf;
R10 is independently selected at each occurrence from the group: a bond to Sf, COOR11, OH, NHR11, C1-5 alkyl substituted with 0-1 R12, and C1-5 alkoxy substituted with 0-1 R12;
R11 is independently selected at each occurrence from the group: H, aryl substituted with 0-1 R12, C3-10 cycloalkyl substituted with 0-1 R12, amino acid substituted with 0-1 R12, and a bond to Sf;
R12 is a bond to Sf;
k is selected from 0, 1, and 2;
h is selected from 0, 1, and 2;
hxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
hxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
g is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
gxe2x80x3xe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
s is selected from 0, 1, 2, 3, 4, and 5;
sxe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
sxe2x80x3 is selected from 0, 1, 2, 3, 4, and 5;
t is selected from 0, 1, 2, 3, 4, and 5;
txe2x80x2 is selected from 0, 1, 2, 3, 4, and 5;
and a pharmaceutically acceptable salt thereof.
In another even more preferred embodiment, the present invention provides a novel ultrasound contrast agent composition, comprising:
(a) a compound comprising: a targeting ligand of the present invention, a surfactant and a linking group between the targeting ligand and the surfactant;
(b) a parenterally acceptable carrier; and,
(c) an echogenic gas.
In another still more preferred embodiment, the ultrasound contrast agent further comprises: 1,2-dipalmitoyl-sn-glycero-3-phosphotidic acid, 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine, and N-(methoxypolyethylene glycol 5000 carbamoyl)-1,2-dipalmitoyl-sn-glycero-3-phosphatidylethanolamine.
In another further preferred embodiment, the echogenic gas is a C2-5 perfluorocarbon.
In another even more preferred embodiment, the present; invention provides a novel therapeutic radiopharmaceutical composition, comprising:
(a) a therapeutic radiopharmaceutical of the present invention; and,
(b) a parenterally acceptable carrier.
In another even more preferred embodiment, the present invention provides a novel diagnostic radiopharmaceutical composition, comprising:
(a) a diagnostic radiopharmaceutical, a MRI contrast agent, or a X-ray contrast agent of the present invention; and,
(b) a parenterally acceptable carrier.
In another even more preferred embodiment, the present invention provides a novel therapeutic radiopharmaceutical composition, comprising: a radiolabelled targeting moiety, wherein the targeting moiety is a compound Q and the radiolabel is a therapeutic isotope selected from the group: 35S, 32P, 125I, 131I, and 211At.
In another further preferred embodiment, the present invention provides a novel therapeutic radiopharmaceutical composition, comprising: a radiolabelled targeting moiety, wherein the targeting moiety is a compound Q and the radiolabel is a therapeutic isotope which is 131I.
In another embodiment, the present invention provides diagnostic kits for the preparation of radiopharmaceuticals useful as imaging agents for cancer or imaging agents for imaging formation of new blood vessels. Diagnostic kits of the present invention comprise one or more vials containing the sterile, non-pyrogenic, formulation comprised of a predetermined amount of a reagent of the present invention, and optionally other components such as one or two ancillary, ligands, reducing agents, transfer ligands, buffers, lyophilization aids, stabilization aids, solubilization aids and bacteriostats. The inclusion of one or more optional components in the formulation will frequently improve the ease of synthesis of the radiopharmaceutical by the practicing end user, the ease of manufacturing the kit, the shelf-life of the kit, or the stability and shelf-life of the radiopharmaceutical. The inclusion of one or two ancillary ligands is required for diagnostic kits comprising, reagent comprising a hydrazine or hydrazone bonding moiety. The one or more vials that contain all or part of the formulation can independently be in the form of a sterile solution or a lyophilized solid.
In another embodiment, the present invention provides an arginine or arginine mimetic containing acyclic or cyclic peptide that targets a biological receptor, wherein the improvement comprises: replacement of the arginine or arginine mimetic with a group of formula IIIa or IIIb: 
The compounds herein described may have asymmetric centers. Unless otherwise indicated, all chiral, diastereomeric and racemic forms are included in the present invention. Many geometric isomers of olefins, Cxe2x95x90N double bonds, and the like can also be present in the compounds described herein, and all such stable isomers are contemplated in the present invention. It will be m appreciated that compounds of the present invention contain asymmetrically substituted carbon atoms, and may be isolated in optically active or racemic forms. It is well known in the art how to prepare optically active forms, such as by resolution of racemic forms or by synthesis from optically active starting materials. Two distinct isomers (cis and trans) of the peptide bond are known to occur; both can also be present in the compounds described herein, and all such stable isomers are contemplated in the present invention. The D and L-isomers of a particular amino acid are designated herein using the conventional 3-letter abbreviation of the amino acid, as indicated by the following examples: D-Leu, or L-Leu.
When any variable occurs more than one time in any substituent or in any formula, its definition on each occurrence is independent of its definition at every other occurrence. Thus, for example, if a group is shown to be substituted with 0-2 R52, then said group may optionally be substituted with up to two R52, and R52 at each occurrence is selected independently from the defined list of possible R52. Also, by way of example, for the group xe2x80x94N(R53)2, each of the two R53 substituents on N is independently selected from the defined list of possible R53. Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. When a bond to a substituent is shown to cross the bond connecting two atoms in a ring, then such substituent may be bonded to any atom on the ring.
As used herein, the term xe2x80x9camino protecting groupxe2x80x9d (or xe2x80x9cN-protectedxe2x80x9d) refers to any group known in the art of organic synthesis for the protection of amine groups. As used herein, the term xe2x80x9camino protecting group reagentxe2x80x9d refers to any reagent known in the art of organic synthesis. for the protection of amine groups that may be reacted with an amine to provide an amine protected with an amine-protecting group. Such amine protecting groups include those listed in Greene and Wuts, xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d John Wiley and Sons, New York (1991) and xe2x80x9cThe Peptides: Analysis, Synthesis, Biology, Vol. 3, Academic Press, New York, (1981), the disclosure of which is hereby incorporated by reference. Examples of amine protecting groups include, but are not limited to, the following: 1) acyl types such as formyl, trifluoroacetyl (TFA), phthalyl, and p-toluenesulfonyl; 2) aromatic carbamate types such as benzyloxycarbonyl (cbz) and substituted benzyloxycarbonyls, 2-(p-biphenyl)-1-methylethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (Fmoc); 3) aliphatic carbamate types such as tert-butyloxycarbonyl (Boc), ethoxycarbonyl, diisopropylmethoxycarbonyl, and allyloxycarbonyl; 4) cyclic alkyl carbamate types such as cyclopentyloxycarbonyl and adamantyloxycarbonyl; 5) alkyl types such as triphenylmethyl and benzyl; 6) trialkylsilane such as trimethylsilane; and 7) thiol containing types such as phenylthiocarbonyl and dithiasuccinoyl.
Amine protecting groups may include, but are not limited to the following: 2,7-di-t-butyl-[9-(10,10-dioxo-10,10,10,10-tetratydrothio-xanthyl)]methyloxycarboneyl; 2-trimethylsilylethyloxycarbonyl; 2-phenylethyloxycarbonyl; 1,1-dimethyl-2,2-dibromoethyloxycarbonyl; 1-methyl-1-(4-biphenylyl)ethyloxycarbonyl; benzyloxycarbonyl, p-nitrobenzyloxycarbonyl; 2-(p-toluenesulfonyl)ethyloxycarbonyl; m-chloro-p-acyloxybenzyloxycarbonyl; 5-benzyisoxazolylmethyloxycrbonyl; p-(dihydroxyboryl)benzyloxycarbonyl; m-nitrophenyloxycarbonyl; o-nitrobenzyloxycarbonyl; 3,5-dimethoxybenzyloxycrbonyl; 3,4-dimethoxy-6-nitrobenzyloxycarbonyl; Nxe2x80x2-p-toluenesulfonylaminocarbonyl; t-amyloxycarbonyl; p-decyloxybenzyloxycarbonyl; diisopropylmethyloxycarbonyl; 2,2-dimethoxycarbonylvinyloxycarbonyl; di(2-pyridyl)methyloxycarbonyl; 2-furanylmethyloxycarbonyl; phthalimide; dithiasuccinimide; 2,5-dimethylpyrrole; benzyl; 5-dibenzylsuberyl; triphenylmethyl; benzylidene; diphenylmethylene; and, methanesulfonamide.
By xe2x80x9creagentxe2x80x9d is meant a compound of this invention capable of direct transformation into a metallopharmaceutical of this invention. Reagents may be utilized directly for the preparation of the metallopharmaceuticals of this invention or may be a component in a kit of this invention.
The term xe2x80x9cbinding agentxe2x80x9d means a metallopharmaceutical of this invention having affinity for and capable of binding to the vitronectin receptor. The binding agents of this invention preferably have Ki less than 1000 nM.
Metallopharmaceutical as used herein is intended to refer to a pharmaceutically acceptable compound containing a metal, wherein the compound is useful for imaging, magnetic resonance imaging, contrast imaging, or x-ray imaging The metal is the cause of the imageable signal in diagnostic applications and the source of the cytotoxic radiation in radiotherapeutic applications. Radiopharmaceuticals are metallopharmaceuticals in which the metal is a radioisotope.
By xe2x80x9cstable compoundxe2x80x9d or xe2x80x9cstable structurexe2x80x9d is meant herein a compound that is sufficiently robust to survive. isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious pharmaceutical agent.
The term ""substitutedxe2x80x9d, as used herein, means that one or more hydrogens on the designated atom or group is replaced with a selection from the indicated group, provided that the designated atom""s or group""s normal valency is not exceeded, and that the substitution results in a stable compound. When a substituent is keto (i.e., xe2x95x90O), then 2 hydrogens on the atom are replaced.
The term xe2x80x9cbondxe2x80x9d, as used herein, means either a single or double bond.
The term xe2x80x9csaltxe2x80x9d, as used herein, is used as defined in the CRC Handbook of Chemistry and Physics, 65th Edition, CRC Press, Boca Raton, Fla. 1984, as any substance which yields ions, other than hydrogen or hydroxyl ions. As used herein, xe2x80x9cpharmaceutically acceptable saltsxe2x80x9d refer to derivatives of the disclosed compounds modified by making acid or base salts. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like.
The phrase xe2x80x9cpharmaceutically acceptablexe2x80x9d is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, commensurate with a reasonable benefit/risk ratio.
As used herein, xe2x80x9cpharmaceutically acceptable saltsxe2x80x9d refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. The pharmaceutically acceptable salts include the conventional non-toxic salts or the quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include those derived from inorganic acids such as hydrochloric, hydrobromic, sulfuric, sulfamic, phosphoric, nitric and the like; and the salts prepared from organic acids such as acetic, propionic, succinic, glycolic, stearic, lactic, tartaric, citric, ascorbic, pamoic, maleic, hydroxymaleic, phenylacetic, glutamic, benzoic, salicylic, sulfanilic, 2-acetoxybenzoic, fumaric, toluenesulfonic, methanesulfonic, ethane disulfonic, oxalic, isethionic, and the like.
The pharmaceutically acceptable salts of the present invention can be synthesized from the parent compound which contains a basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting the free acid or base forms of these compounds with a stoichiometric amount of the appropriate base or acid in water or in an organic solvent, or in a mixture of the two; generally, nonaqueous media like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile are preferred. Lists of suitable salts are found in Remington""s Pharmaceutical Sciences, 17th ed., Mack Publishing Company, Easton, Pa., 1985, p. 1418, the disclosure of which is hereby incorporated by reference.
As used herein, xe2x80x9calkylxe2x80x9d is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms. C1-10 alkyl, is intended to include C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10 alkyl groups. Examples of alkyl include, but are not limited to, methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl, t-butyl, n-pentyl, and s-pentyl. xe2x80x9cHaloalkylxe2x80x9d is intended to include both branched and straight-chain saturated aliphatic hydrocarbon groups having the specified number of carbon atoms, substituted with 1 or more halogen (for example xe2x80x94CvFw where v=1 to 3 and w=1 to (2v+1)). Examples of haloalkyl include, but are not limited to, trifluoromethyl, trichloromethyl, pentafluoroethyl, and pentachloroethyl. xe2x80x9cAlkoxyxe2x80x9d represents an alkyl group as defined above with the indicated number of carbon atoms attached through an oxygen bridge. C1-10 alkoxy, is intended to include C1, C2, C3, C4, C5, C6, C7, C8, C9, and C10 alkoxy groups. Examples of alkoxy include, but are not limited to, methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy, t-butoxy, n-pentoxy, and s-pentoxy. xe2x80x9cCycloalkylxe2x80x9d is intended to include saturated ring groups, such as cyclopropyl, cyclobutyl, or cyclopentyl. C3-7 cycloalkyl, is intended to include C3, C4, C5, C6, and C7 cycloalkyl groups Alkenylxe2x80x9d is intended to include hydrocarbon chains of either. a straight or branched configuration and one or more unsaturated carbon-carbon bonds which may occur in any. stable point along the chain, such as ethenyl and propenyl. C2-10 alkenyl, is intended to include C2, C3, C4, C5, C6, C7, C5, C9, and C10 alkenyl groups. xe2x80x9cAlkynylxe2x80x9d is intended to include hydrocarbon chains of either a straight or branched configuration and one or more triple carbon-carbon bonds which may occur in any stable point along the chain, such as ethynyl and propynyl. C2-10 alkynyl, is intended to include C2, C3, C4, C5, C6, C7, C5, C9, and C10 alkynyl groups.
As used herein, xe2x80x9ccarbocyclexe2x80x9d or xe2x80x9ccarbocyclic residuexe2x80x9d is intended to mean any stable 3, 4, 5, 6, or 7-membered monocyclic or bicyclic or 7, 8, 9, 10, 11, 12, or 13-membered bicyclic or tricyclic, any of which may be saturated, partially unsaturated, or aromatic. Examples of such carbocycles include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, adamantyl, cyclooctyl, [3.3.0]bicyclooctane, [4.3.0]bicyclononane, [4.4.0]bicyclodecane, [2.2.2]bicyclooctane, fluorenyl, phenyl, naphthyl, indanyl, adamantyl, and tetrahydronaphthyl.
As used herein, the term xe2x80x9calkarylxe2x80x9d means an aryl group bearing an alkyl group of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms; the term xe2x80x9caralkylxe2x80x9d means an alkyl group of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms bearing an aryl group; the term xe2x80x9carylalkarylxe2x80x9d means an aryl group bearing an alkyl group of 1-10 carbon atoms bearing an aryl group; and the term xe2x80x9cheterocycloalkylxe2x80x9d means an alkyl group of 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 carbon atoms bearing a heterocycle.
As used herein, the term xe2x80x9cheterocyclexe2x80x9d or xe2x80x9cheterocyclic systemxe2x80x9d is intended to mean a stable 5, 6, or 7-membered monocyclic or bicyclic or 7, 8, 9, or 10-membered bicyclic heterocyclic ring which is saturated, partially unsaturated or unsaturated (aromatic), and which consists of carbon atoms and 1, 2, 3, or 4 heteroatoms independently selected; from the group consisting of N, NH, O and S and including any bicyclic group in which any of the above-defined heterocyclic rings is fused to a benzene ring. The nitrogen and sulfur heteroatoms may optionally be oxidized. The heterocyclic ring may be attached to its pendant group at any heteroatom or carbon atom that results in a stable structure. The heterocyclic rings described herein may be substituted on carbon or on a nitrogen atom if the resulting compound is stable. A nitrogen in the heterocycle may optionally be quaternized. It is preferred that when the total number of S and O atoms in the heterocycle exceeds 1, then these heteroatoms are not adjacent to one another. It is preferred that the total number of S and O atoms in the heterocycle is not more than 1. As used herein, the term xe2x80x9caromatic heterocyclic systemxe2x80x9d or xe2x80x9cheteroarylxe2x80x9d is intended to mean a stable 5, 6, or 7-membered monocyclic or bicyclic or 7, 8, 9, or 10-membered bicyclic heterocyclic aromatic ring which consists of carbon atoms and 1, 2, 3, or 4 heterotams independently selected from the group consisting of N, NH, O and S. It is to be noted that total number of S and O atoms in the aromatic heterocycle is not more than 1.
Examples of heterocycles include, but are not limited to, acridinyl, azocinyl, benzimidazolyl, benzofuranyl, benzothiofuranyl, benzothiophenyl, benzoxazolyl, benzthiazolyl, benztriazolyl, benztetrazolyl, benzisoxazolyl, benzisothiazolyl, benzimidazolinyl, carbazolyl, 4aH-carbazolyl, carbolinyl, chromanyl, chromenyl, cinnolinyl, decahydroquinolinyl, 2H,6H-1,5,2-dithiazinyl, dihydrofuro[2,3-b]tetrahydrofuran, furanyl, furazanyl, imidazolidinyl, imidazolinyl, imidazolyl, 1H-indazolyl, indolenyl, indolinyl, indolizinyl, indolyl, 3H-indolyl, isobenzofuranyl, isochromanyl, isoindazolyl, isoindolinyl, isoindolyl, isoquinolinyl, isothiazolyl, isoxazolyl, methylenedioxyphenyl, morpholinyl, naphthyridinyl, octahydroisoquinolinyl, oxadiazolyl, 1,2,3-oxadiazolyl, 1,2,4-oxadiazolyl, 1,2,5-oxadiazolyl, 1,3,4-oxadiazolyl, oxazolidinyl, oxazolyl, oxazolidinyl, pyrimidinyl, phenanthridinyl, phenanthrolinyl, phenazinyl, phenothiazinyl, phenoxathiinyl, phenoxazinyl, phthalazinyl, piperazinyl, piperidinyl, piperidonyl, 4-piperidonyl, piperonyl, pteridinyl, purinyl, pyranyl, pyrazinyl, pyrazolidinyl, pyrazolinyl, pyrazolyl, pyridazinyl, pyridooxazole, pyridoimidazole, pyridothiazole, pyridinyl, pyridyl, pyrimidinyl, pyrrolidinyl, pyrrolinyl, 2H-pyrrolyl, pyrrolyl, quinazolinyl, quinolinyl, 4H-quinolizinyl, quinoxalinyl, quinuclidinyl, tetrahydrofuranyl, tetrahydroisoquinolinyl, tetrahydroquinolinyl, tetrazolyl, 6H-1,2,5-thiadiazinyl, 1,2,3-thiadiazolyl, 1,2,4-thiadiazolyl, 1,2,5-thiadiazolyl, 1,3,4-thiadiazolyl, thianthrenyl, thiazolyl, thienyl, thienothiazolyl, thienooxazolyl, thienoimidazolyl, thiophenyl, triazinyl, 1,2,3-triazolyl, 1,2,4-triazolyl, 1,2,5-triazolyl, 1,3,4-triazolyl, and xanthenyl. Preferred heterocycles include, but are not limited to, pyridinyl, furanyl, thienyl, pyrrolyl, pyrazolyl, pyrrolidinyl, imidazolyl, indolyl, benzimidazolyl, 1H-indazolyl, oxazolidinyl, benzotriazolyl, benzisoxazolyl, oxindolyl, benzoxazolinyl, and isatinoyl. Also included are fused ring and spiro compounds containing, for example, the above heterocycles.
A xe2x80x9cpolyalkylene glycolxe2x80x9d is a polyethylene glycol, polypropylene glycol or polybutylene glycol having a molecular weight of less than about 5000, terminating in either a hydroxy or alkyl ether moiety.
A xe2x80x9ccarbohydratexe2x80x9d is a polyhydroxy aldehyde, ketone, alcohol or acid, or derivatives thereof, including polymers thereof having polymeric linkages of the acetal type.
A xe2x80x9ccyclodextrinxe2x80x9d is a cyclic oligosaccharide. Examples of cyclodextrins include, but are not limited to, xcex1-cyclodextrin, hydroxyethyl-xcex1-cyclodextrin, hydroxypropyl-xcex1-cyclodextrin, xcex2-cyclodextrin, hydroxypropyl-xcex2-cyclodextrin, carboxymethyl-xcex2-cyclodextrin, dihydroxypropyl-xcex2-cyclodextrin, hydroxyethyl-xcex2-cyclodextrin, 2,6 di-O-methyl-xcex2-cyclodextrin, sulfated-xcex2-cyclodextrin, xcex3-cyclodextrin, hydroxypropyl-xcex3-cyclodextrin, dihydroxypropyl-xcex3-cyclodextrin, hydroxyethyl-xcex3-cyclodextrin, and sulfated xcex3-cyclodextrin.
As used herein, the term xe2x80x9cpolycarboxyalkylxe2x80x9d means an alkyl group having between two and about 100 carbon atoms and a plurality of carboxyl substituents; and the term xe2x80x9cpolyazaalkylxe2x80x9d means a linear or branched alkyl group having between two and about 100 carbon atoms, interrupted by or substituted with a plurality of amine groups.
A xe2x80x9creducing agentxe2x80x9d is a compound that reacts with a radionuclide, which is typically obtained as a relatively unreactive, high oxidation state compound, to lower its oxidation state by transferring electron(s) to the radionuclide, thereby making it more reactive. Reducing agents useful in the preparation of radiopharmaceuticals and in diagnostic kits useful for the preparation of said radiopharmaceuticals include but are not limited to stannous chloride, stannous fluoride, formamidine sulfinic acid, ascorbic acid, cysteine, phosphines, and cuprous or ferrous salts. Other reducing agents are described in Brodack et. al., PCT Application 94/22496, which is incorporated herein by reference.
A xe2x80x9ctransfer ligandxe2x80x9d is a ligand that forms an intermediate complex with a metal ion that is stable enough to prevent unwanted side-reactions but labile enough to be converted to a metallopharmaceutical. The formation of the intermediate complex is kinetically favored while the formation of the metallopharmaceutical is thermodynamically favored. Transfer ligands useful in the preparation of metallopharmaceuticals and in diagnostic kits useful for the preparation of diagnostic radiopharmaceuticals include but are not limited to gluconate, glucoheptonate, mannitol, glucarate, N,N,Nxe2x80x2,Nxe2x80x2-ethylenediaminetetraacetic acid, pyrophosphate and methylenediphosphonate. In general, transfer ligands are comprised of oxygen or nitrogen donor. atoms.
The term xe2x80x9cdonor atomxe2x80x9d refers to the atom directly attached to a metal by a chemical bond.
xe2x80x9cAncillaryxe2x80x9d or xe2x80x9cco-ligandsxe2x80x9d are ligands that are incorporated into a radiopharmaceutical during its synthesis. They serve to complete the coordination sphere of the radionuclide together with the chelator or radionuclide bonding unit of the reagent. For radiopharmaceuticals comprised of a binary ligand system, the radionuclide coordination sphere is composed of one or more chelators or bonding units from one or more reagents and one or more ancillary or co-ligands, provided that there are a total of two types of ligands, chelators or bonding units. For example, a radiopharmaceutical comprised of one chelator or bonding unit from one reagent and two of the same ancillary or co-ligands and a radiopharmaceutical comprised of two chelators or bonding units from one or two reagents and one ancillary or co-ligand are both considered to be comprised of-binary ligand systems. For radiopharmaceuticals comprised of a ternary ligand system, the radionuclide coordination sphere is composed of one or more chelators or bonding units from one or more reagents and one or more of two different types of ancillary or co-ligands, provided that there are a total of three types of ligands, chelators or bonding units. For example, a radiopharmaceutical comprised of one chelator or bonding unit from one reagent and two different ancillary or co-ligands is considered to be comprised of a ternary ligand system.
Ancillary or co-ligands useful in the preparation of radiopharmaceuticals and in diagnostic kits useful for the preparation of said radiopharmaceuticals are comprised of one or more oxygen, nitrogen, carbon, sulfur, phosphorus, arsenic, selenium, and tellurium donor atoms. A ligand can be a transfer ligand in the synthesis of a radiopharmaceutical and also serve as an ancillary or co-ligand in another radiopharmaceutical. Whether a ligand is termed a transfer or ancillary or co-ligand depends on whether the ligand remains in the radionuclide coordination sphere in the radiopharmaceutical, which is determined by the coordination chemistry of the radionuclide and the chelator or bonding unit of the reagent or reagents.
A xe2x80x9cchelatorxe2x80x9d or xe2x80x9cbonding unitxe2x80x9d is the moiety or group on a reagent that binds to a metal ion through the formation of chemical bonds with one or more donor atoms.
The term xe2x80x9cbinding sitexe2x80x9d means the site in vivo or in vitro that binds a biologically active molecule.
A xe2x80x9cdiagnostic kitxe2x80x9d or xe2x80x9ckitxe2x80x9d comprises a collection of components, termed the formulation, in one or more vials which are used by the practicing end user in a clinical or pharmacy setting to synthesize diagnostic radiopharmaceuticals. The kit provides all the requisite components to synthesize and use the diagnostic radiopharmaceutical except those that are commonly available to the practicing end user, such as water or saline for injection, a solution of the radionuclide, equipment for heating the kit during the synthesis of the radiopharmaceutical, if required, equipment necessary for administering the radiopharmaceutical to the patient such as syringes and shielding, and imaging equipment.
Therapeutic radiopharmaceuticals, X-ray contrast agent pharmaceuticals, ultrasound contrast agent pharmaceuticals and metallopharmaceuticals for magnetic resonance imaging contrast are provided to the end user in their-final form in a formulation contained typically in one vial, as either a lyophilized solid or an aqueous solution. The end user reconstitutes the lyophilized with water or saline and withdraws the patient dose or just withdraws the dose from the aqueous solution formulation as provided.
A xe2x80x9clyophilization aidxe2x80x9d is a component that has favorable physical properties for lyophilization, such as the glass transition temperature, and is added to the formulation to improve the physical properties of the combination of all the components of the formulation for lyophilization.
A xe2x80x9cstabilization aidxe2x80x9d is a component that is added to the metallopharmaceutical or to the diagnostic kit either to stabilize the metallopharmaceutical or to prolong the shelf-life of the kit before it must be used. Stabilization aids can be antioxidants, reducing agents or radical scavengers and can provide improved stability by reacting preferentially with species that degrade other components or the metallopharmaceutical.
A xe2x80x9csolubilization aidxe2x80x9d is a component that improves the solubility of one or more other components in the medium required for the formulation.
A xe2x80x9cbacteriostatxe2x80x9d is a component that inhibits the growth of bacteria in a formulation either during its storage before use of after a diagnostic kit is used to, synthesize a radiopharmaceutical
The term xe2x80x9camino acidxe2x80x9d as used herein means an organic compound containing both a basic amino group and an acidic carboxyl group. Included within this term are natural amino acids (e.g., L-amino acids), modified and unusual amino acids (e.g., D-amino acids), as well as amino acids which are known to occur biologically in free or combined form but usually do not occur in proteins. Included within this term are modified and unusual amino acids, such as those disclosed in, for example, Roberts and Vellaccio (1983) The Peptides, 5: 342-429, the teaching of which is hereby incorporated by reference. Natural protein occurring amino acids include, but are not limited to, alanine, arginine, asparagine, aspartic acid, cysteine, glutamic acid, glutamine, glycine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, serine, threonine, tyrosine, tyrosine, tryptophan, proline, and valine. Natural non-protein amino acids include, but are not limited to arginosuccinic acid, citrulline, cysteine sulfinic acid, 3,4-dihydroxyphenylalanine, homocysteine, homoserine, ornithine, 3-monoiodotyrosine, 3,5-diiodotryosine, 3,5,5xe2x80x2-triiodothyronine, and 3,3xe2x80x2,5,5xe2x80x2-tetraiodothyronine. Modified or unusual amino acids which can be used to practice the invention include, but are not limited to, D-amino acids, hydroxylysine, 4-hydroxyproline, an Nxe2x80x94Cbz-protected amino acid, 2,4-diaminobutyric acid, homoarginine, norleucine, N-methylaminobutyric acid, naphthylalanine, phenylglycine, xcex2-phenylproline, tert-leucine, 4-aminocyclohexylalanine, N-methyl-norleucine, 3,4-dehydroproline, N,N-dimethylaminoglycine, N-methylaminoglycine, 4-aminopiperidine-4-carboxylic acid, 6-aminocaproic acid, trans-4-(aminomethyl)-cyclohexanecarboxylic acid, 2-, 3-, and 4-(aminomethyl)-benzoic acid, 1-aminocyclopentanecarboxylic acid, 1-aminocyclopropanecarboxylic acid, and 2-benzyl-5-aminopentanoic acid.
The term xe2x80x9cpeptidexe2x80x9d as used herein means a linear compound that consists of two or more amino acids (as defined herein) that are linked by means of a peptide bond. A xe2x80x9cpeptidexe2x80x9d as used in the presently claimed invention is intended to refer to a moiety with a molecular weight of less than 10,000 Daltons, preferable less than 5,000 Daltons, and more preferably less than 2,500 Daltons. The term xe2x80x9cpeptidexe2x80x9d also includes compounds containing both peptide and non-peptide components, such as pseudopeptide or peptidomimetic residues or other non-amino acid components. Such a compound containing both peptide and non-peptide components may also be referred to as a xe2x80x9cpeptide analogxe2x80x9d.
A xe2x80x9cpseudopeptidexe2x80x9d or xe2x80x9cpeptidomimeticxe2x80x9d is a compound which mimics the structure of an amino acid residue or a peptide, for example, by using linking groups other than amide linkages between the peptide mimetic and an amino acid residue (pseudopeptide bonds) and/or by using non-amino acid substituents and/or a modified amino acid residue. A xe2x80x9cpseudopeptide residuexe2x80x9d means that portion of an pseudopeptide or peptidomimetic that is present in a peptide.
The term xe2x80x9cpeptide bondxe2x80x9d means a covalent amide linkage formed by loss of a molecule of water between the carboxyl group of one amino acid and the amino group of a second amino acid.
The term xe2x80x9cpseudopeptide bondsxe2x80x9d includes peptide bond isosteres which may be used in place of or as substitutes for the normal amide linkage. These substitute or amide xe2x80x9cequivalentxe2x80x9d linkages are formed from combinations of atoms not normally found in peptides or proteins which mimic the spatial requirements of the amide bond and which should stabilize the molecule to enzymatic degradation.
The following conventional three-letter amino acid abbreviations are used herein; the conventional one-letter amino acid abbreviations are NOT used herein:
Ala=alanine
Arg=arginine
Asn=asparagine
Asp=aspartic acid
Cys=cysteine
Gln=glutamine
Glu=glutamic acid
Gly=glycine
His=histidine
Ile=isoleucine
Leu=leucine
Lys=lysine
Met=methionine
Nle=norleucine
Orn=ornithine
Phe=phenylalanine
Phg=phenylglycine
Pro=proline
Sar=sarcosine
Ser=serine
Thr=threonine
Trp=tryptophan
Tyr=tyrosine
Val=valine
The targeting moieties of the present invention, preferably, have a binding affinity for their respective target of less than 1000 nM. More preferably, the targeting moieties of the present invention, preferably, have a binding affinity of less than 100 nM. Even more preferably, the targeting moieties of the present invention, preferably, have a binding affinity of less than 10 nM.
Sf as used herein is a surfactant that is either a lipid or a compound of the formula A1-E-A2, defined above. The surfactant is intended to form a vesicle (e.g., a microsphere) capable of containing an echogenic gas. The ultrasound contrast agent compositions of the present invention are intended to be capable upon agitation (e.g., shaking, stirring, etc.) of encapsulating an echogenic gas in a vescicle in such a way as to allow for the resultant product to be useful as an ultrasound contrast agent.
xe2x80x9cVesiclexe2x80x9d refers to a spherical entity that is characterized by the presence of an internal void. Preferred vesicles are formulated from lipids, including the various lipids described herein. In any given vesicle, the lipids may be in the form of a monolayer or bilayer, and the mono- or bilayer lipids may be used to form one of more mono- or bilayers. In the case of more than one mono- or bilayer, the mono- or bilayers are generally concentric. The lipid vesicles described herein include such entities commonly referred to as liposomes, micelles, bubbles, microbubbles, microspheres and the like. Thus, the lipids may be used to form a unilamellar vesicle (comprised of one monolayer or bilayer), an oligolamellar vesicle (comprised of about two or about three monolayers or bilayers) or a multilamellar vesicle (comprised of more than about three monolayers or bilayers). The internal void of the vesicles may be filled with a liquid, including, for example, an aqueous liquid, a gas, a gaseous precursor, and/or a solid or solute material, including, for example, a bioactive agent, as desired.
xe2x80x9cVesicular compositionxe2x80x9d refers to a composition which is formulate from lipids and which comprises vesicles.
xe2x80x9cVesicle formulationxe2x80x9d refers to a composition which comprises vesicles and a bioactive agent.
Microsphere, as used herein, is preferably a sphere of less than or equal to 10 microns. Liposome, as used herein, may include a single lipid layer (a lipid monolayer), two lipid layers (a lipid bilayer) or more than two lipid layers (a lipid multilayer). xe2x80x9cLipsomesxe2x80x9d refers to a generally spherical cluster or aggregate of amphipathic compounds, including lipid compounds, typically in the form of one or more concentric layers, for example, bilayers. They may also be referred to herein as lipid vesicles.
The term xe2x80x9cbubblesxe2x80x9d, as used herein, refers to vesicles which are generally characterized by the presence of one or more membranes or walls surrounding an internal void that is filled with a gas or precursor thereto. Exemplary bubbles include, for example, liposomes, micelles and the like.
xe2x80x9cLipidxe2x80x9d refers to a synthetic or naturally-occurring amphipathic compound which comprises a hydrophilic component and a hydrophobic component. Lipids include, for example, fatty acids, neutral fats, phosphatides, glycolipids, aliphatic alchols and waxes, terpenes and steroids.
xe2x80x9cLipid compositionxe2x80x9d refers to a composition that comprises a lipid compound. Exemplary lipid compositions include suspensions, emulsions and vesicular compositions.
xe2x80x9cLipid formulationxe2x80x9d refers to a composition that comprises a lipid compound and a bioactive agent.
Examples of classes of suitable lipids and specific suitable lipids include: phosphatidylcholines,such as dioleoylphosphatidylcholine, dimyristoylphosphatidylcholine, dipalmitoylphosphatidylcholine (DPPC), and distearoylphosphatidylcholine; phosphatidylethanolamines, such as dipalmitoylphosphatidylethanolamine (DPPE), dioleoylphosphatidylethanolamine and N-succinyl-dioleoylphosphatidylethanolamine; phosphatidylserines; phosphatidylglycerols; sphingolipids; glycolipids, such as ganglioside GM1; glucolipids; sulfatides; glycosphingolipids; phosphatidic acids, such as dipalmatoylphosphatidic acid (DPPA); palmitic fatty acids; stearic fatty acids; arachidonic fatty acids; lauric fatty acids; myristic fatty acids; lauroleic fatty acids; physeteric fatty acids; myristoleic fatty acids; palmitoleic fatty acids; petroselinic fatty acids; oleic fatty acids; isolauric fatty acids; isomyristic fatty acids; isopalmitic fatty acids; isostearic fatty acids; cholesterol and cholesterol derivatives, such as cholesterol hemisuccinate, cholesterol sulfate, and cholesteryl-(4xe2x80x2-trimethylammonio)-butanoate; polyoxyethylene fatty acid esters; polyoxyethylene fatty acid alcohols; polyoxyethylene fatty acid alcohol ethers; polyoxyethylated sorbitan fatty acid esters; glycerol polyethylene glycol oxystearate; glycerol polyethylene glycol ricinoleate; ethoxylated soybean sterols; ethoxylated castor oil; polyoxyethylene-polyoxypropylene fatty acid polymers; polyoxyethylene fatty acid stearates; 12-(((7xe2x80x2-diethylaminocoumarin-3-yl)-carbonyl)-methylamino)-octadecanoic acid; N-[12-(((7xe2x80x2-diethylamino-coumarin-3-yl)-carbonyl)-methylamino)octadecanoyl]-2-amino-palmitic acid; 1,2-dioleoyl-sn-glycerol; 1,2-dipalmitoyl-sn-3-succinylglycerol; 1,3-dipalmitoyl-2-succinyl-glycerol; and 1-hexadecyl-2-palmitoyl-glycerophosphoethanolamine and palmitoylhomocysteine; lauryltrimethylammonium bromide; cetyltrimethylammonium bromide; myristyltrimethylammonium bromide; alkyldimethylbenzylammonium chlorides,such as wherein alkyl is a C12, C14 or C16 alkyl; benzyldimethyldodecylammonium bromide; benzyldimethyldodecylammonium chloride, benzyldimethylhexadecylammonium bromide; benzyldimethylhexadecylammonium chloride; benzyldimethyltetradecylammonium bromide; benzyldimethyltetradecylammonium chloride; cetyldimethylethylammonium bromide; cetyldimethylethylammonium chloride; cetylpyridinium bromide; cetylpyridinium chloride; N-[1,2,3-dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTMA); 1,2-dioleoyloxy-3-(trimethylammonio)propane (DOTAP); and 1,2-dioleoyl-c-(4xe2x80x2-trimethylammonio)-butanoyl-sn-glycerol (DOTB).
The echogenic gas may be one gas or mixture of gases, such as CF4, C2F6, C3F8, cyclo-C4F8, C4F10, C5F12, cyclo-C5F10,cyclo-C4F7 (1-trifluoromethyl), propane (2-trifluoromethyl)-1,1,1,3,3,3 hexafluoro, and butane (2-trifluoromethyl)-1,1,1,3,3,3,4,4,4 nonafluoro. Also preferred are the the corresponding unsaturated versions of the above compounds, for example C2F4, C3F6, the isomers of C4F8. Also, mixtures of these gases, especially mixtures of perfluorocarbons with other perfluorocarbons and mixtures of perfluorocarbons with other inert gases, such as air, N2, O2, He, would be useful. Examples of these can be found in Quay, U.S. Pat. No. 5,595,723, the contents of which are herein incorporated by reference.
X-ray contrast agents of the present invention are comprised of one or more angiogenic tumor vasculature targeting moieties attached to one or more X-ray absorbing or xe2x80x9cheavyxe2x80x9d atoms of atomic number 20 or greater, further comprising an optional linking moiety, Ln, between the targeting moieties and the x-ray absorbing atoms. The frequently used heavy atom in X-ray contrast agents is iodine. Recently, X-ray contrast agents comprised of metal chelates (Wallace, R., U.S. Pat. No. 5,417,959) and polychelates comprised of a plurality of metal ions (Love, D., U.S. Pat. No. 5,679,810) have been disclosed. More recently, multinuclear cluster complexes have been disclosed as X-ray contrast agents (U.S. Pat. No. 5,804,161, PCT WO91/14460, and PCT WO 92/17215). Examples of X-ray agents include the non-radioactive or naturally occurring analogs of the above listed radionuclides (e.g., Re, Sm, Ho, Lu, Pm, Y, Bi, Pd, Gd, La, Au, Au, Yb, Dy, Cu, Rh, Ag, and Ir).
MRI contrast agents of the present invention are comprised of one or more angiogenic tumor vasculature targeting moieties attached to one or more paramagnetic metal ions, further comprising an optional linking moiety, Ln, between the targeting moieties and the paramagnetic metal ions. The paramagnetic metal ions are present in the form of metal complexes or metal oxide particles. U.S. Pat. Nos. 5,412,148 and 5,760,191 describe examples of chelators for paramagnetic metal ions for use in MRI contrast agents. U.S. Pat. Nos. 5,801,228, 5,567,411, and 5,281,704 describe examples of polychelants useful for complexing more than one paramagnetic metal ion for use in MRI contrast agents. U.S. Pat. No. 5,520,904 describes particulate compositions comprised of paramagnetic metal ions for use as MRI contrast agents.
The pharmaceuticals of the present invention can be synthesized by several approaches. One approach involves the synthesis of the targeting peptide or peptidomimetic moiety, Q, and direct attachment of one or more moieties, Q to one or more metal chelators or bonding moieties, Ch, or to a paramagnetic metal ion or heavy atom containing solid particle, or to an echogenic gas microbubble. Another approach involves the attachment of one or more moieties, Q to the linking group, Ln, which is then attached to one or more metal chelators or bonding moieties, Ch, or to a paramagnetic metal ion or heavy atom containing solid particle, or to an echogenic gas microbubble. Another approach, useful in the synthesis of pharmaceuticals wherein d is 1, involves the synthesis of the moiety, Qxe2x80x94Ln, together, by incorporating an amino acid or amino acid mimetic residue bearing Ln into the synthesis of the peptide or peptidomimetic. The resulting moiety, Qxe2x80x94Ln, is then attached to one or more metal chelators or bonding moieties, Ch, or to a paramagnetic metal ion or heavy atom containing solid particle, or to an echogenic gas microbubble. Another approach involves the synthesis of a peptide or peptidomimetic, Q, bearing a fragment of the linking group, Ln, one or more of which are then attached to the remainder of the linking group and then to one or more metal chelators or bonding moieties, Ch, or to a paramagnetic metal ion or heavy atom containing solid particle, or to an echogenic gas microbubble.
The peptides or peptidomimetics, Q, optionally bearing a linking group, Ln, or a fragment of the linking group, can be synthesized using standard synthetic methods known to those skilled in the art. Preferred methods include but are not limited to those methods described below.
Generally, peptides and peptidomimetics are elongated by deprotecting the alpha-amine of the C-terminal residue and coupling the next suitably protected amino acid through a peptide linkage using the methods described. This deprotection and coupling procedure is repeated until the desired sequence is obtained. This coupling can be performed with the constituent amino acids in a stepwise fashion, or condensation of fragments (two to several amino acids), or combination of both processes, or by solid phase peptide synthesis according to the method originally described by Merrifield, J. Am. Chem. Soc., 85, 2149-2154 (1963), the disclosure of which is hereby incorporated by reference.
The peptides and peptidomimetics may also be synthesized using automated synthesizing equipment. In addition to the foregoing, procedures for peptide and peptidomimetic synthesis are described in Stewart and Young, xe2x80x9cSolid Phase Peptide Synthesisxe2x80x9d, 2nd ed, Pierce Chemical Co., Rockford, Ill. (1984); Gross, Meienhofer, Udenfriend, Eds., xe2x80x9cThe Peptides: Analysis, Synthesis, Biology, Vol. 1, 2, 3, 5, and 9, Academic Press, New York, (1980-1987); Bodanszky, xe2x80x9cPeptide Chemistry: A Practical Textbookxe2x80x9d, Springer-Verlag, New York (1988); and Bodanszky et al. xe2x80x9cThe Practice of Peptide Synthesisxe2x80x9d Springer-Verlag, New York (1984), the disclosures of which are hereby incorporated by reference.
The coupling between two amino acid derivatives, an amino acid and a peptide or peptidomimetic, two peptide or peptidomimetic fragments, or the cyclization of a peptide or peptidomimetic can be carried out using standard coupling procedures such as the azide method, mixed carbonic acid anhydride (isobutyl chloroformate) method, carbodiimide (dicyclohexylcarbodiimide, diisopropylcarbodiimide, or water-soluble carbodiimides) method, active ester (p-nitrophenyl ester, N-hydroxysuccinic imido ester) method, Woodward reagent K method, carbonyldiimidazole method, phosphorus reagents such as BOP-Cl, or oxidation-reduction method. Some of these methods (especially the carbodiimide) can be enhanced by the addition of 1-hydroxybenzotriazole. These coupling reactions may be performed in either solution (liquid phase) or solid phase.
The functional groups of the constituent amino acids or amino acid mimetics must be protected during the coupling reactions to avoid undesired bonds being formed. The protecting groups that can be used are listed in Greene, xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d John Wiley and Sons, New York (1981) and xe2x80x9cThe Peptides: Analysis, Synthesis, Biology, Vol., 3, Academic Press, New York (1981), the disclosure of which is hereby incorporated by reference.
The alpha-carboxyl group of the C-terminal residue is usually protected by an ester that can be cleaved to give the carboxylic acid. These protecting groups include: 1) alkyl esters such as methyl and t-butyl, 2) aryl esters such as benzyl and substituted benzyl, or 3) esters which can be cleaved by mild base treatment or mild reductive means such as trichloroethyl and phenacyl esters. In the solid phase case, the C-terminal amino acid is attached to an insoluble carrier (usually polystyrene). These insoluble carriers contain a group which will react with the carboxyl group to form a bond which is stable to the elongation conditions but readily cleaved later. Examples of which are: oxime resin (DeGrado and Kaiser (1980) J. Org. Chem. 45, 1295-1300) chloro or bromomethyl resin, hydroxymethyl resin, and aminomethyl resin. Many of these resins are commercially available with the desired C-terminal amino acid already incorporated.
The alpha-amino group of each amino acid must be protected. Any protecting group known in the art can be used. Examples of these are: 1) acyl types such as formyl, trifluoroacetyl, phthalyl, and p-toluenesulfonyl; 2) aromatic carbamate types such as benzyloxycarbonyl (Cbz) and substituted benzyloxycarbonyls, 1-(p-biphenyl)-1-methylethoxycarbonyl, and 9-fluorenylmethyloxycarbonyl (Fmoc); 3) aliphatic carbamate types such as tert-butyloxycarbonyl (Boc), ethoxycarbonyl, diisopropylmethoxycarbonyl, and allyloxycarbonyl; 4) cyclic alkyl carbamate types such as cyclopentyloxycarbonyl and adamantyloxycarbonyl; 5) alkyl types such as triphenylmethyl and benzyl; 6) trialkylsilane such as trimethylsilane; and 7) thiol containing types such as phenylthiocarbonyl and dithiasuccinoyl. The preferred alpha-amino protecting group is either Boc or Fmoc. Many amino acid or amino acid mimetic derivatives suitably protected for peptide synthesis are commercially available.
The alpha-amino protecting group is cleaved prior to the coupling of the next amino acid. When the Boc-group is used, the methods of choice are trifluoroacetic acid, neat or in dichloromethane, or HCl in dioxane. The resulting ammonium salt is then neutralized either prior to the coupling or in situ with basic solutions such as aqueous buffers, or tertiary amines in dichloromethane or dimethylformamide. When the Fmoc group is used, the reagents of choice are piperidine or substituted piperidines in dimethylformamide, but any secondary amine or aqueous basic solutions can be used. The deprotection is carried out at a temperature between 0xc2x0 C. and room temperature.
Any of the amino acids or amino acid mimetics bearing side chain functionalities must be protected during the preparation of the peptide using any of the above-identified groups. Those skilled in the art will appreciate that the selection and use of appropriate protecting groups for these side chain functionalities will depend upon the amino acid or amino acid mimetic and presence of other protecting groups in the peptide or peptidomimetic. The selection of such a protecting group is important in that it must not be removed during the deprotection and coupling of the alpha-amino group.
For example, when Boc is chosen for the alpha-amine protection the following protecting groups are acceptable: p-toluenesulfonyl (tosyl) moieties and nitro for arginine; benzyloxycarbonyl, substituted benzyloxycarbonyls, tosyl or trifluoroacetyl for lysine; benzyl or alkyl esters such as cyclopentyl for glutamic and aspartic acids; benzyl ethers for serine and threonine; benzyl ethers, substituted benzyl ethers or 2-bromobenzyloxycarbonyl for tyrosine; p-methylbenzyl, p-methoxybenzyl, acetamidomethyl, benzyl, or t-butylsulfonyl for cysteine; and the indole of tryptophan can either be left unprotected or protected with a formyl group.
When Fmoc is chosen for the alpha-amine protection usually tert-butyl based protecting groups are acceptable. For instance, Boc can be used for lysine, tert-butyl ether for serine, threonine and tyrosine, and tert-butyl ester for glutamic and aspartic acids.
Once the elongation of the peptide or peptidomimetic, or the elongation and cyclization of a cyclic peptide or peptidomimetic is completed all of the protecting groups are removed. For the liquid phase synthesis the protecting groups are removed in whatever manner as dictated by the choice of protecting groups. These procedures are well known to those skilled in the art.
When a solid phase synthesis is used to synthesize a cyclic peptide or peptidomimetic, the peptide or peptidomimetic should be removed from the resin without simultaneously removing protecting groups from functional groups that might interfere with the cyclization process. Thus, if the peptide or peptidomimetic is to be cyclized in solution, the cleavage conditions need to be chosen such that a free a-carboxylate and a free a-amino group are generated without simultaneously removing other protecting groups. Alternatively, the peptide or peptidomimetic may be removed from the resin by hydrazinolysis, and then coupled by the azide method. Another very convenient method involves the synthesis of peptides or peptidomimetics on an oxime resin, followed by intramolecular nucleophilic displacement from the resin, which generates a cyclic peptide or peptidomimetic (Osapay, Profit, and Taylor (1990) Tetrahedron Letters 43, 6121-6124). When the oxime resin is employed, the Boc protection scheme is generally chosen. Then, the preferred method for removing side chain protecting groups generally involves treatment with anhydrous HF containing additives such as dimethyl sulfide, anisole, thioanisole, or p-cresol at 0xc2x0 C. The cleavage of the peptide or peptidomimetic can also be accomplished by other acid reagents such as trifluoromethanesulfonic acid/trifluoroacetic acid mixtures.
Unusual amino acids used in this invention can be synthesized by standard methods familiar to those skilled in the art (xe2x80x9cThe Peptides: Analysis, Synthesis, Biology, Vol. 5, pp. 342-449, Academic Press, New York (1981)). N-Alkyl amino acids can be prepared using procedures described in previously (Cheung et al., (1977) Can. T. Chem. 55, 906; Freidinger et al., (1982) J. Org. Chem. 48, 77 (1982)), which are incorporated herein by reference.
Additional synthetic procedures that can be used by one of skill in the art to synthesize the peptides and peptidomimetics targeting moieties are described in PCT WO94/22910, the contents of which are herein incorporated by reference.
The attachment of linking groups, Ln, to the peptides and peptidomimetics, Q; chelators or bonding units, Ch, to the peptides and peptidomimetics, Q, or to the linking groups, Ln; and peptides and peptidomimetics bearing a fragment of the linking group to the remainder of the linking group, in combination forming the moiety, (Q)dxe2x80x94Ln, and then to the moiety Ch; can all be performed by standard techniques. These include, but are not limited to, amidation, esterification, alkylation, and the formation of ureas or thioureas. Procedures for performing these attachments can be found in Brinkley, M., Bioconjugate Chemistry 1992, 3(1), which is incorporated herein by reference.
A number of methods can be used to attach the peptides and peptidomimetics, Q, to paramagnetic metal ion or heavy atom containing solid particles, X2, by one of skill in the art of the surface modification of solid particles. In general, the targeting moiety Q or the combination (Q)dLn is attached to a coupling group that react with a constituent of the surface of the solid particle. The coupling groups can be any of a number of silanes which react with surface hydroxyl groups on the solid particle surface, as described in co-pending U.S. application Ser. No. 60/092,360, and can also include polyphosphonates, polycarboxylates, polyphosphates or mixtures thereof which couple with the surface of the solid particles, as described in U.S. Pat. No. 5,520,904.
A number of reaction schemes can be used to attach the peptides and peptidomimetics, Q, to the surfactant microsphere, X3. These are illustrated in following reaction schemes where Sf represents a surfactant moiety that forms the surfactant microsphere.
Acylation Reaction:
Sfxe2x80x94C(xe2x95x90O)xe2x80x94Y+Qxe2x80x94NH2 or xe2x86x92Sfxe2x80x94C(xe2x95x90O)xe2x80x94NHxe2x80x94Q
Qxe2x80x94OH or Sfxe2x80x94C(xe2x95x90O)xe2x80x94Oxe2x80x94Q
Y is a leaving group or active ester
Disulfide Coupling:
Sfxe2x80x94SH+Qxe2x80x94SHxe2x86x92Sfxe2x80x94Sxe2x80x94Sxe2x80x94Q
Sulfonamide Coupling:
Sfxe2x80x94S(xe2x95x90O)2xe2x80x94Y+Qxe2x80x94NH2xe2x86x92Sfxe2x80x94S(xe2x95x90O)2xe2x80x94NHxe2x80x94Q
Reductive Amidation:
Sfxe2x80x94CHO+Qxe2x80x94NH2xe2x86x92Sfxe2x80x94NHxe2x80x94Q
In these reaction schemes, the substituents Sf and Q can be reversed as well.
The linking group Ln can serve several roles. First it provides a spacing group between the metal chelator or bonding moiety, Ch, the paramagnetic metal ion or heavy atom containing solid particle, X2, and the surfactant microsphere, X3, and the one or more of the peptides or peptidomimetics, Q, so as to minimize the possibility that the moieties Cxe2x80x94X, Chxe2x80x94X1, X2, and X3, will interfere with the interaction of the recognition sequences of Q with angiogenic tumor vasculature receptors. The necessity of incorporating a linking group in a reagent is dependent on the identity of Q, Chxe2x80x94X, Chxe2x80x94X1, X2, and X3. If Chxe2x80x94X, Chxe2x80x94X1, X2, and X3, cannot be attached to Q without substantially diminishing its affinity for the receptors, then a linking group is used. A linking group also provides a means of independently attaching multiple peptides and peptidomimetics, Q, to one group that is attached to Chxe2x80x94X, Chxe2x80x94X1, X2, or X3.
The linking group also provides a means of incorporating a pharmacokinetic modifier into the pharmaceuticals of the present invention. The pharmacokinetic modifier serves to direct the biodistibution of the injected pharmaceutical other than by the interaction of the targeting moieties, Q, with the receptors expressed in the tumor neovasculature. A wide variety of functional groups can serve as pharmacokinetic modifiers, including, but not limited to, carbohydrates, polyalkylene glycols, peptides or other polyamino acids, and cyclodextrins. The modifiers can be used to enhance or decrease hydrophilicity and to enhance or decrease the rate of blood clearance. The modifiers can also be used to direct the route of elimination of the pharmaceuticals. Preferred pharmacokinetic modifiers are those that result in moderate to fast blood clearance and enhanced renal excretion.
The metal chelator or bonding moiety, Ch, is selected to form stable complexes with the metal ion chosen for the particular application. Chelators or bonding moieties for diagnostic radiopharmaceuticals are selected to form stable complexes with the radioisotopes that have imageable gamma ray or positron emissions, such as 99mTc, 95Tc, 111In, 62Cu, 60Cu, 64Cu, 67Ga, 68Ga, 86Y.
Chelators for technetium, copper and gallium isotopes are selected from diaminedithiols, monoamine-monoamidedithiols, triamide-monothiols, monoamine-diamide-monothiols, diaminedioximes, and hydrazines. The chelators are generally tetradentate with donor atoms selected from nitrogen, oxygen and sulfur. Preferred reagents are comprised of chelators having amine nitrogen and thiol sulfur donor atoms and hydrazine bonding units. The thiol sulfur atoms and the hydrazines may bear a protecting group which can be displaced either prior to using the reagent to synthesize a radiopharmaceutical or preferably in situ during the synthesis of the radiopharmaceutical.
Exemplary thiol protecting groups include those listed in Greene and Wuts, xe2x80x9cProtective Groups in Organic Synthesisxe2x80x9d John Wiley and Sons, New York (1991), the disclosure of which is hereby incorporated by reference. Any thiol protecting group known in the art can be used. Examples of thiol protecting groups include, but are not limited to, the following: acetamidomethyl, benzamidomethyl, 1-ethoxyethyl, benzoyl, and triphenylmethyl.
Exemplary protecting groups for hydrazine bonding units are hydrazones which can be aldehyde or ketone hydrazones having substituents selected from hydrogen, alkyl, aryl and heterocycle. Particularly preferred hydrazones are described in co-pending U.S. Ser. No. 08/476,296 the disclosure of which is herein incorporated by reference in its entirety.
The hydrazine bonding unit when bound to a metal radionuclide is termed a hydrazido, or diazenido group and serves as the point of attachment of the radionuclide to the remainder of the radiopharmaceutical. A diazenido group can be either terminal (only one atom of the group is bound to the radionuclide) or chelating. In order to have a chelating diazenido group at least one other atom of the group must also be bound to the radionuclide. The atoms bound to the metal are termed donor atoms.
Chelators for 111In and 86Y are preferably selected from cyclic and acyclic polyaminocarboxylates such as DTPA, DOTA, DO3A, 2-benzyl-DOTA, alpha-(2-phenethyl)1,4,7,10-tetraazazcyclododecane-1-acetic-4,7,10-tris(methylacetic)acid, 2-benzyl-cyclohexyldiethylenetriaminepentaacetic acid, 2-benzyl-6-methyl-DTPA, and 6,6xe2x80x3-bis[N,N,Nxe2x80x3,Nxe2x80x3-tetra(carboxymethyl)aminomethyl)-4xe2x80x2-(3-amino-4-methoxyphenyl)-2,2xe2x80x2:6xe2x80x2,2xe2x80x3-terpyridine. Procedures for synthesizing these chelators that are not commercially available can be found in Brechbiel, M. and Gansow, O., J. Chem. Soc. Perkin Trans. 1992, 1, 1175; Brechbiel, M. and Gansow, O., Bioconjugate Chem. 1991, 2, 187; Deshpande, S., et. al., J. Nucl. Med. 1990, 31, 473; Kruper, J., U.S. Pat. No. 5,064,956, and Toner, J., U.S. Pat. No. 4,859,777, the disclosures of which are hereby incorporated by reference in their entirety.
The coordination sphere of metal ion includes all the ligands or groups bound to the metal. For a transition metal radionuclide to be stable it typically has a coordination number (number of donor atoms) comprised of an integer greater than or equal to 4 and less than or equal to 8; that is there are 4 to 8 atoms bound to the metal and it is said to have a complete coordination sphere. The requisite coordination number for a stable radionuclide complex is determined by the identity of the radionuclide, its oxidation state, and the type of donor atoms. If the chelator or bonding unit does not provide all of the atoms necessary to stabilize the metal radionuclide by completing its coordination sphere, the coordination sphere is completed by donor atoms from other ligands, termed ancillary or co-ligands, which can also be either terminal or chelating.
A large number of ligands can serve as ancillary or co-ligands, the choice of which is determined by a variety of considerations such as the ease of synthesis of the radiopharmaceutical, the chemical and physical properties of the ancillary ligand, the rate of formation, the yield, and the number of isomeric forms of the resulting radiopharmaceuticals, the ability to administer said ancillary or co-ligand to a patient without adverse physiological consequences to said patient, and the compatibility of the ligand in a lyophilized kit formulation. The charge and lipophilicity of the ancillary ligand will affect the charge and lipophilicity of the radiopharmaceuticals. For example, the use of 4,5-dihydroxy-1,3-benzene disulfonate results in radiopharmaceuticals with an additional two anionic groups because the sulfonate groups will be anionic under physiological conditions. The use of N-alkyl substituted 3,4-hydroxypyridinones results in radiopharmaceuticals with varying degrees of lipophilicity depending on the size of the alkyl substituents.
Preferred technetium radiopharmaceuticals of the present invention are comprised of a hydrazido or diazenido bonding unit and an ancillary ligand, AL1, or a bonding unit and two types of ancillary AL1 and AL2, or a tetradentate chelator comprised of two nitrogen and two sulfur atoms. Ancillary ligands AL1 are comprised of two or more hard donor atoms such as oxygen and amine nitrogen (sp3 hybridized). The donor atoms occupy at least two of the sites in the coordination sphere of the radionuclide metal; the ancillary ligand AL1 serves as one of the three ligands in the ternary ligand system. Examples of ancillary ligands AL1 include but are not limited to dioxygen ligands and functionalized. aminocarboxylates. A large number of such ligands are available from commercial sources.
Ancillary dioxygen ligands include ligands that coordinate to the metal ion through at least two oxygen donor atoms. Examples include but are not limited to: glucoheptonate, gluconate, 2-hydroxyisobutyrate, lactate, tartrate, mannitol, glucarate, maltol, Kojic acid, 2,2-bis(hydroxymethyl)propionic acid, 4,5-dihydroxy-1,3-benzene disulfonate, or substituted or unsubstituted 1,2 or 3,4 hydroxypyridinones. (The names for the ligands in these examples refer to either the protonated or non-protonated forms of the ligands.)
Functionalized aminocarboxylates include ligands that have a combination of amine nitrogen and oxygen donor atoms. Examples include but are not limited to: iminodiacetic acid, 2,3-diaminopropionic acid, nitrilotriacetic acid, N,Nxe2x80x2-ethylenediamine diacetic acid, N,N,Nxe2x80x2-ethylenediamine triacetic acid, hydroxyethylethylenediamine triacetic acid, and N,Nxe2x80x2-ethylenediamine bis-hydroxyphenylglycine. (The names for the ligands in these examples refer to either the protonated or non-protonated forms of the ligands.)
A series of functionalized aminocarboxylates are disclosed by Bridger et. al. in U.S. Pat. No. 5,350,837, herein incorporated by reference, that result in improved rates of formation of technetium labeled hydrazino modified proteins. We have determined that certain of these aminocarboxylates result in improved yields of the radiopharmaceuticals of the present invention. The preferred ancillary ligands AL1 functionalized aminocarboxylates that are derivatives of glycine; the most preferred is tricine (tris(hydroxymethyl)methylglycine).
The most preferred technetium radiopharmaceuticals of the present invention are comprised of a hydrazido or diazenido bonding unit and two types of ancillary designated AL1 and AL2, or a diaminedithiol chelator. The second type of ancillary ligands AL2 are comprised of one or more soft donor atoms selected from the group: phosphine phosphorus, arsine arsenic, imine nitrogen (sp2 hybridized), sulfur (sp2 hybridized) and carbon (sp hybridized); atoms which have p-acid character Ligands AL2 can be monodentate, bidentate or tridentate, the denticity is defined by the number of donor atoms in the ligand. One of the two donor atoms in a bidentate ligand and one of the three donor atoms in a tridentate ligand must be a soft donor atom. We have disclosed in co-pending U.S. Ser. No. 08/415,908, and U.S. Ser. Nos. 60/013360 08/646,886, the disclosures of which are herein incorporated by reference in their entirety, that radiopharmaceuticals comprised of one or more ancillary or co-ligands AL2 are more stable compared to radiopharmaceuticals that are not comprised of one or more ancillary ligands, AL2; that is, they have a minimal number of isomeric forms, the relative ratios of which do not change significantly with time, and that remain substantially intact upon dilution.
The ligands AL2 that are comprised of phosphine or arsine donor atoms are trisubstituted phosphines, trisubstituted arsines, tetrasubstituted diphosphines and tetrasubstituted diarsines. The ligands AL2 that are comprised of imine nitrogen are unsaturated or aromatic nitrogen-containing, 5 or 6-membered heterocycles. The ligands that are comprised of sulfur (sp2 hybridized) donor atoms are thiocarbonyls, comprised of the moiety Cxe2x95x90S. The ligands comprised of carbon (sp hybridized) donor atoms are isonitriles, comprised of the moiety CNR, where R is an organic radical. A large number of such ligands are available from commercial sources. Isonitriles can be synthesized as described in European Patent 0107734 and in U.S. Pat. No. 4,988,827, herein incorporated by reference.
Preferred ancillary ligands AL2 are trisubstituted phosphines and unsaturated or aromatic 5 or 6 membered heterocycles. The most preferred ancillary ligands AL2 are trisubstituted phosphines and unsaturated 5 membered heterocycles.
The ancillary ligands AL2 may be substituted with alkyl, aryl, alkoxy, heterocycle, aralkyl, alkaryl and arylalkaryl groups and may or may not bear functional groups comprised of heteroatoms such as oxygen, nitrogen, phosphorus or sulfur. Examples of such functional groups include but are not limited to: hydroxyl, carboxyl, carboxamide, nitro, ether, ketone, amino, ammonium, sulfonate, sulfonamide, phosphonate, and phosphonamide. The functional groups may be chosen to alter the lipophilicity and water solubility of the ligands that may affect the biological properties of the radiopharmaceuticals, such as altering the distribution into non-target tissues, cells or fluids, and the mechanism and rate of elimination from the body.
Chelators or bonding moieties for therapeutic radiopharmaceuticals are selected to form stable complexes with the radioisotopes that have alpha particle, beta particle, Auger or Coster-Kronig electron emissions, such as 186Re, 188Re, 153Sm, 166Ho, 177Lu, 149Pm, 90Y, 212Bi, 103Pd, 109Pd, 159Gd, 140La, 198Au, 199Au, 169Yb, 175Yb, 165Dy, 166Dy, 67Cu, 105Rh, 111Ag, and 192Ir. Chelators for rhenium, copper, palladium, platinum, iridium, rhodium, silver and gold isotopes are selected from diaminedithiols, monoamine-monoamidedithiols, triamide-monothiols, monoamine-diamide-monothiols, diaminedioximes, and hydrazines. Chelators for yttrium, bismuth, and the lanthanide isotopes are selected from cyclic and acyclic polyaminocarboxylates such as DTPA, DOTA, DO3A, 2-benzyl-DOTA, alpha-(2-phenethyl)1,4,7,10-tetraazacyclododecane-1-acetic-4,7,10-tris(methylacetic)acid, 2-benzyl-cyclohexyldiethylenetriaminepentaacetic acid, 2-benzyl-6-methyl-DTPA, and 6,6xe2x80x3-bis(N,N,Nxe2x80x3,Nxe2x80x3-tetra(carboxymethyl)aminomethyl)-4xe2x80x2-(3-amino-4-methoxyphenyl)-2,2xe2x80x2:6xe2x80x2,2xe2x80x3-terpyridine.
Chelators for magnetic resonance imaging contrast agents are selected to form stable complexes with paramagnetic metal ions, such as Gd(III), Dy(III), Fe(III), and Mn(II), are selected from cyclic and acyclic polyaminocarboxylates such as DTPA, DOTA, DO3A, 2-benzyl-DOTA, alpha-(2-phenethyl)1,4,7,10-tetraazacyclododecane-1-acetic-4,7,10-tris(methylacetic)acid, 2-benzyl-cyclohexyldiethylenetriaminepentaacetic acid, 2-benzyl-6-methyl-DTPA, and 6,6xe2x80x3-bis[N,N,Nxe2x80x3,Nxe2x80x3-tetra(carboxymethyl)aminomethyl)-4xe2x80x3-(3-amino-4-methoxyphenyl)-2,2xe2x80x2:6xe2x80x2,2xe2x80x3-terpyridine.
The technetium and rhenium radiopharmaceuticals of the present invention comprised of a hydrazido or diazenido bonding unit can be easily prepared by admixing a salt of a radionuclide, a reagent of the present invention, an ancillary ligand AL1, an ancillary ligand AL2, and a reducing agent, in an aqueous solution at temperatures from 0 to 100xc2x0 C. The technetium and rhenium radiopharmaceuticals of the present invention comprised of a tetradentate chelator having two nitrogen and two sulfur atoms can be easily prepared by admixing a salt of a radionuclide, a reagent of the present invention, and a reducing agent, in an aqueous solution at temperatures from 0 to 100xc2x0 C.
When the bonding unit in the reagent of the present invention is present as a hydrazone group, then it must first be converted to a hydrazine, which may or may not be protonated, prior to complexation with the metal radionuclide. The conversion of the hydrazone group to the hydrazine can occur either prior to reaction with the radionuclide, in which case the radionuclide and the ancillary or co-ligand or ligands are combined not with the reagent but with a hydrolyzed form of the reagent bearing the chelator or bonding unit, or in the presence of the radionuclide in which case the reagent itself is combined with the radionuclide and the ancillary or co-ligand or ligands. In the latter case, the pH of the reaction mixture. must be neutral or acidic.
Alternatively, the radiopharmaceuticals of the present invention comprised of a hydrazido or diazenido bonding unit can be prepared by first admixing a salt of a radionuclide, an ancillary ligand AL1, and a reducing agent in an aqueous solution at temperatures from 0 to 100xc2x0 C. to form an intermediate radionuclide complex with the ancillary ligand AL1 then adding a reagent of the present invention and an ancillary ligand AL2 and reacting further at temperatures from 0 to 100xc2x0 C.
Alternatively, the radiopharmaceuticals of the present invention comprised of a hydrazido or diazenido bonding unit can be prepared by first admixing a salt of a radionuclide, an ancillary ligand AL1, a reagent of the present invention, and a reducing agent in an aqueous solution at temperatures from 0 to 100xc2x0 C. to form an intermediate radionuclide complex, and then adding an ancillary ligand AL2 and reacting further at temperatures from 0 to 100xc2x0 C.
The technetium and rhenium radionuclides are preferably in the chemical form of pertechnetate or perrhenate and a pharmaceutically acceptable cation. The pertechnetate salt form is preferably sodium pertechnetate such as obtained from commercial Tc-99m generators. The amount of pertechnetate used to prepare the radiopharmaceuticals of the present invention can range from 0.1 mCi to 1 Ci, or more preferably from 1 to 200 mCi.
The amount of the reagent of the present invention used to prepare the technetium and rhenium radiopharmaceuticals of the present invention can range from 0.01 pg to 10 mg, or more preferably from 0.5 xcexcg to 200 xcexcg. The amount used will be dictated by the amounts of the other reactants and the identity of the radiopharmaceuticals of the present invention to be prepared.
The amounts of the ancillary ligands AL1 used can range from 0.1 mg to 1 g, or more preferably from 1 mg to 100 mg. The exact amount for a particular radiopharmaceutical is a function of identity of the radiopharmaceuticals of the present invention to be prepared, the procedure used and the amounts and identities of the other reactants. Too large an amount of AL1 will result in the formation of by-products comprised of technetium labeled AL1 without a biologically active molecule or by-products comprised of technetium labeled biologically active molecules with the ancillary ligand AL1 but without the ancillary ligand AL2. Too small an amount of AL1 will result in other by-products such as technetium labeled biologically active molecules with the ancillary ligand AL2 but without the ancillary ligand AL1, or reduced hydrolyzed technetium, or technetium colloid.
The amounts of the ancillary ligands AL2 used can range from 0.001 mg to 1 g, or more preferably from 0.01 mg to 10 mg. The exact amount for a particular radiopharmaceutical is a function of the identity of the radiopharmaceuticals of the present invention to be prepared, the procedure used and the amounts and identities of the other reactants. Too large an amount of AL2 will result in the formation of by-products comprised of technetium labeled AL2 without a biologically active molecule or by-products comprised of technetium labeled biologically active molecules with the ancillary ligand AL2 but without the ancillary ligand AL1. If the reagent bears one or more substituents that are comprised of a soft donor atom, as defined above, at least a ten-fold molar excess of the ancillary ligand AL2 to the reagent of formula 2 is required to prevent the substituent from interfering with the coordination of the ancillary ligand AL2 to the metal radionuclide.
Suitable reducing agents for the synthesis of the radiopharmaceuticals of the present invention include stannous salts, dithionite or bisulfite salts, borohydride salts, and formamidinesulfinic acid, wherein the salts are of any pharmaceutically acceptable form. The preferred reducing agent is a stannous salt. The amount of a reducing agent used can range from 0.001 mg to 10 mg, or more preferably from 0.005 mg to 1 mg.
The specific structure of a radiopharmaceutical of the present invention comprised of a hydrazido or diazenido bonding unit will depend on the identity of the reagent of the present invention used, the identity of any ancillary ligand AL1, the identity of any ancillary ligand AL2, and the identity of the radionuclide. Radiopharmaceuticals comprised of a hydrazido or diazenido bonding unit synthesized using concentrations of reagents of  less than 100 xcexcg/mL, will be comprised of one hydrazido or diazenido group. Those synthesized using  greater than 1 mg/mL concentrations will be comprised of two hydrazido or diazenido groups from two reagent molecules. For most applications, only a limited amount of the biologically active molecule can be injected and not result in undesired side-effects, such as chemical toxicity, interference with a biological process or an altered biodistribution of the radiopharmaceutical. Therefore, the radiopharmaceuticals that require higher concentrations of the reagents comprised in part of the biologically active molecule, will have to be diluted or purified after synthesis to avoid such side-effects.
The identities and amounts used of the ancillary ligands AL1 and AL2 will determine the values of the variables y and z. The values of y and z can independently be an integer from 1 to 2. In combination, the values of y and z will result in a technetium coordination sphere that is made up of at least five and no more than seven donor atoms. For monodentate ancillary ligands AL2, z can be an integer from 1 to 2; for bidentate or tridentate ancillary ligands AL2, z is 1. The preferred combination for monodentate ligands is y equal to 1 or 2 and z equal to 1. The preferred combination for bidentate or tridentate ligands is y equal to 1 and z equal to 1.
The indium, copper, gallium, silver, palladium, rhodium, gold, platinum; bismuth, yttrium and lanthanide radiopharmaceuticals of the present invention can be easily prepared by admixing a salt of a radionuclide and a reagent of the present invention, in an aqueous solution at temperatures from 0 to 100xc2x0 C. These radionuclides are typically obtained as a dilute aqueous solution in a mineral acid, such as hydrochloric, nitric or sulfuric acid. The radionuclides are combined with from one to about one thousand equivalents of the reagents of the present invention dissolved in aqueous solution. A buffer is typically used to maintain the pH of the reaction mixture between 3 and 10.
The gadolinium, dysprosium, iron and manganese metallopharmaceuticals of the present invention can be easily prepared by admixing a salt of the paramagnetic metal ion and a reagent of the present invention, in an aqueous solution at temperatures from 0 to 100xc2x0 C. These paramagnetic metal ions are typically obtained as a dilute aqueous solution in a mineral acid, such as hydrochloric, nitric or sulfuric acid. The paramagnetic metal ions are combined with from one to about one thousand equivalents of the reagents of the present invention dissolved in aqueous solution. A buffer is typically used to maintain the pH of the reaction mixture between 3 and 10.
The total time of preparation will vary depending on the identity of the metal ion, the identities and amounts of the reactants and the procedure used for the preparation. The preparations may be complete, resulting in  greater than 80% yield of the radiopharmaceutical, in 1 minute or may require more time. If higher purity metallopharmaceuticals are needed or desired, the products can be purified by any of a number of techniques well known to those skilled in the art such as liquid chromatography, solid phase extraction, solvent extraction, dialysis or ultrafiltration.
Buffers useful in the preparation of metallopharmaceuticals and in diagnostic kits useful for the preparation of said radiopharmaceuticals include but are not limited to phosphate, citrate, sulfosalicylate, and acetate. A more complete list can be found in the United States. Pharmacopeia.
Lyophilization aids useful in the preparation of diagnostic kits useful for the preparation of radiopharmaceuticals include but are not limited to mannitol, lactose, sorbitol, dextran, Ficoll, and polyvinylpyrrolidine (PVP).
Stabilization aids useful in the preparation of metallopharmaceuticals and in diagnostic kits useful for the preparation of radiopharmaceuticals include but are not limited to ascorbic acid, cysteine, monothioglycerol, sodium bisulfite, sodium metabisulfite, gentisic acid, and inositol.
Solubilization aids useful in the preparation of metallopharmaceuticals and in diagnostic kits useful for the preparation of radiopharmaceuticals include but are not limited to ethanol, glycerin, polyethylene glycol, propylene glycol, polyoxyethylene sorbitan monooleate, sorbitan monoloeate, polysorbates, poly(oxyethylene)poly(oxypropylene)poly(oxyethylene) block copolymers (Pluronics) and lecithin. Preferred solubilizing aids are polyethylene glycol, and Pluronics.
Bacteriostats useful in the preparation of metallopharmaceuticals and in diagnostic kits useful for the preparation of radiopharmaceuticals include but are not limited to benzyl alcohol, benzalkonium chloride, chlorbutanol, and methyl, propyl or butyl paraben.
A component in a diagnostic kit can also serve more than one function. A reducing agent can also serve as a stabilization aid, a buffer can also serve as a transfer ligand, a lyophilization aid can also serve as a transfer, ancillary or co-ligand and so forth.
The diagnostic radiopharmaceuticals are administered by intravenous injection, usually in saline solution, at a dose of 1 to 100 mCi per 70 kg body weight, or preferably at a dose of 5 to 50 mCi. Imaging is performed using known procedures.
The therapeutic radiopharmaceuticals are administered by intravenous injection, usually in saline solution, at a cl dose of 0.1 to 100 mCi per 70 kg body weight, or preferably at a dose of 0.5 to 5 mCi per 70 kg body weight.
The magnetic resonance imaging contrast agents of the present invention may be used in a similar manner as other MRI agents as described in U.S. Pat. Nos. 5,155,215; 5,087,440; Margerstadt et al., Magn. Reson. Med., 1986, 3, 808; Runge et al., Radiology, 1988, 166, 835; and Bousquet et al., Radiology, 1988, 166, 693. Generally, sterile aqueous solutions of the contrast agents are administered to a patient intravenously in dosages ranging. from 0.01 to 1.0 mmoles per kg body weight.
For use as X-ray contrast agents, the compositions of the present invention should generally have a heavy atom concentration of 1 mM to 5 M, preferably 0.1 M to 2 M. Dosages, administered by intravenous injection, will typically range from 0.5 mmol/kg to 1.5 mmol/kg, preferably 0.8 mmol/kg to 1.2 mmol/kg. Imaging is performed using known techniques, preferably X-ray computed tomography.
The ultrasound contrast agents of the present invention are administered by intravenous injection in an amount of 10 to 30 xcexcL of the echogenic gas per kg body weight or by infusion at a rate of approximately 3 xcexcL/kg/min. Imaging is performed using known techniques of sonography.